World War I
Overview
 
World War I which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war
World war
A world war is a war affecting the majority of the world's most powerful and populous nations. World wars span multiple countries on multiple continents, with battles fought in multiple theaters....

 centred in Europe that began on 28 July 1914 and lasted until 11 November 1918. It involved all the world's great powers, which were assembled in two opposing alliances: the Allies
Allies of World War I
The Entente Powers were the countries at war with the Central Powers during World War I. The members of the Triple Entente were the United Kingdom, France, and the Russian Empire; Italy entered the war on their side in 1915...

 (centred around the Triple Entente
Triple Entente
The Triple Entente was the name given to the alliance among Britain, France and Russia after the signing of the Anglo-Russian Entente in 1907....

 of Britain
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 and Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

) and the Central Powers
Central Powers
The Central Powers were one of the two warring factions in World War I , composed of the German Empire, the Austro-Hungarian Empire, the Ottoman Empire, and the Kingdom of Bulgaria...

 (originally centred around the Triple Alliance
Triple Alliance (1882)
The Triple Alliance was the military alliance between Germany, Austria–Hungary, and Italy, , that lasted from 1882 until the start of World War I in 1914...

 of Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

, Austria-Hungary
Austria-Hungary
Austria-Hungary , more formally known as the Kingdoms and Lands Represented in the Imperial Council and the Lands of the Holy Hungarian Crown of Saint Stephen, was a constitutional monarchic union between the crowns of the Austrian Empire and the Kingdom of Hungary in...

 and Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

).
Timeline

1914    Franz Ferdinand, Archduke of Austria and his wife Sophie are assassinated in Sarajevo by young Serbian nationalist Gavrilo Princip, the ''casus belli'' of World War I.

1914    World War I: Austria-Hungary declares war on Serbia after Serbia rejects the conditions of an ultimatum sent by Austria on July 23 following the assassination of Archduke Francis Ferdinand.

1914    Germany declares war on Russia at the opening of World War I. The Swiss Army mobilises because of World War I

1914    Germany declares war on Russia at the opening of World War I. The Swiss Army mobilises because of World War I

1914    World War I: Germany declares war against France.

1914    World War I: Germany invades Belgium. In response, the United Kingdom declares war on Germany. The United States declare their neutrality.

1914    World War I: the German minelayer ''Königin Luise'' lays a minefield about 40 miles of the Thames Estuary (Lowestoft). She is intercepted and sunk by the British light-cruiser ''HMS Amphion''.

1914    World War I: World War I: World War I: [[First Battle of the Atlantic

1914    World War I: the United Kingdom declares war on Austria-Hungary; the countries of the British Empire follow suit.

1914    World War I: Battle of Cer begins.

Quotations

What passing-bells for these who die as cattle?Only the monstrous anger of the guns.

Wilfred Owen|Wilfred Owen, from Anthem for Doomed Youth|Anthem for Doomed Youth

In war-time the word patriotism means suppression of truth”.

Siegfried Sassoon|Siegfried Sassoon in Memoirs of an Infantry Officer

The day has passed when armies on the ground or navies on the sea can be the arbiter of a nation's destiny in war. The main power of defense and the power of initiative against an enemy has passed to the air.

Brigadier General Billy Mitchell|Billy Mitchell, November 1918

Any one of them could have been me. Millions of men came to fight in this war and I find it incredible that I am the only one left.

Harry Patch|Harry Patch, last surviving veteran to have fought in the trenches of the First World War. Commenting on graves at a Flanders war cemetery, July 2007

Encyclopedia
World War I which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war
World war
A world war is a war affecting the majority of the world's most powerful and populous nations. World wars span multiple countries on multiple continents, with battles fought in multiple theaters....

 centred in Europe that began on 28 July 1914 and lasted until 11 November 1918. It involved all the world's great powers, which were assembled in two opposing alliances: the Allies
Allies of World War I
The Entente Powers were the countries at war with the Central Powers during World War I. The members of the Triple Entente were the United Kingdom, France, and the Russian Empire; Italy entered the war on their side in 1915...

 (centred around the Triple Entente
Triple Entente
The Triple Entente was the name given to the alliance among Britain, France and Russia after the signing of the Anglo-Russian Entente in 1907....

 of Britain
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 and Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

) and the Central Powers
Central Powers
The Central Powers were one of the two warring factions in World War I , composed of the German Empire, the Austro-Hungarian Empire, the Ottoman Empire, and the Kingdom of Bulgaria...

 (originally centred around the Triple Alliance
Triple Alliance (1882)
The Triple Alliance was the military alliance between Germany, Austria–Hungary, and Italy, , that lasted from 1882 until the start of World War I in 1914...

 of Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

, Austria-Hungary
Austria-Hungary
Austria-Hungary , more formally known as the Kingdoms and Lands Represented in the Imperial Council and the Lands of the Holy Hungarian Crown of Saint Stephen, was a constitutional monarchic union between the crowns of the Austrian Empire and the Kingdom of Hungary in...

 and Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

). More than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history. More than 9 million combatants were killed
World War I casualties
The total number of military and civilian casualties in World War I were over 35 million. There were over 15 million deaths and 20 million wounded ranking it among the deadliest conflicts in human history....

, largely because of great technological advances in firepower without corresponding advances in mobility. It was the sixth deadliest conflict in world history, subsequently paving the way for various political changes such as revolutions in the nations involved.

Long-term causes of the war included the imperialistic
Imperialism
Imperialism, as defined by Dictionary of Human Geography, is "the creation and/or maintenance of an unequal economic, cultural, and territorial relationships, usually between states and often in the form of an empire, based on domination and subordination." The imperialism of the last 500 years,...

 foreign policies of the great powers of Europe, including the German Empire
German Empire
The German Empire refers to Germany during the "Second Reich" period from the unification of Germany and proclamation of Wilhelm I as German Emperor on 18 January 1871, to 1918, when it became a federal republic after defeat in World War I and the abdication of the Emperor, Wilhelm II.The German...

, the Austro-Hungarian Empire, the Ottoman Empire, the Russian Empire
Russian Empire
The Russian Empire was a state that existed from 1721 until the Russian Revolution of 1917. It was the successor to the Tsardom of Russia and the predecessor of the Soviet Union...

, the British Empire
British Empire
The British Empire comprised the dominions, colonies, protectorates, mandates and other territories ruled or administered by the United Kingdom. It originated with the overseas colonies and trading posts established by England in the late 16th and early 17th centuries. At its height, it was the...

, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

, and Italy. The assassination on 28 June 1914
Assassination of Archduke Franz Ferdinand of Austria
On 28 June 1914, Archduke Franz Ferdinand of Austria, heir presumptive to the Austro-Hungarian throne, and his wife, Sophie, Duchess of Hohenberg, were shot dead in Sarajevo, by Gavrilo Princip, one of a group of six Bosnian Serb assassins coordinated by Danilo Ilić...

 of Archduke Franz Ferdinand of Austria
Archduke Franz Ferdinand of Austria
Franz Ferdinand was an Archduke of Austria-Este, Austro-Hungarian and Royal Prince of Hungary and of Bohemia, and from 1889 until his death, heir presumptive to the Austro-Hungarian throne. His assassination in Sarajevo precipitated Austria-Hungary's declaration of war against Serbia...

, the heir to the throne of Austria-Hungary
Austria-Hungary
Austria-Hungary , more formally known as the Kingdoms and Lands Represented in the Imperial Council and the Lands of the Holy Hungarian Crown of Saint Stephen, was a constitutional monarchic union between the crowns of the Austrian Empire and the Kingdom of Hungary in...

, by a Yugoslav nationalist was the proximate trigger of the war. It resulted in a Habsburg ultimatum
July Ultimatum
The July Crisis was a diplomatic crisis among the major powers of Europe in the summer of 1914 that led to the First World War...

 against the Kingdom of Serbia
Kingdom of Serbia
The Kingdom of Serbia was created when Prince Milan Obrenović, ruler of the Principality of Serbia, was crowned King in 1882. The Principality of Serbia was ruled by the Karađorđevic dynasty from 1817 onwards . The Principality, suzerain to the Porte, had expelled all Ottoman troops by 1867, de...

. Several alliances formed over the previous decades were invoked, so within weeks the major powers were at war; via their colonies, the conflict soon spread around the world.

On 28 July, the conflict opened with the Austro-Hungarian invasion of Serbia
Serbian Campaign (World War I)
The Serbian Campaign was fought from late July 1914, when Austria-Hungary invaded Serbia at the outset of the First World War, until late 1915, when the Macedonian Front was formed...

, followed by the German invasion of Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

, Luxembourg
Luxembourg
Luxembourg , officially the Grand Duchy of Luxembourg , is a landlocked country in western Europe, bordered by Belgium, France, and Germany. It has two principal regions: the Oesling in the North as part of the Ardennes massif, and the Gutland in the south...

 and France; and a Russian attack against Germany. After the German march on Paris was brought to a halt, the Western Front
Western Front (World War I)
Following the outbreak of World War I in 1914, the German Army opened the Western Front by first invading Luxembourg and Belgium, then gaining military control of important industrial regions in France. The tide of the advance was dramatically turned with the Battle of the Marne...

 settled into a static battle of attrition with a trench line
Trench warfare
Trench warfare is a form of occupied fighting lines, consisting largely of trenches, in which troops are largely immune to the enemy's small arms fire and are substantially sheltered from artillery...

 that changed little until 1917. In the East
Eastern Front (World War I)
The Eastern Front was a theatre of war during World War I in Central and, primarily, Eastern Europe. The term is in contrast to the Western Front. Despite the geographical separation, the events in the two theatres strongly influenced each other...

, the Russian army successfully fought against the Austro-Hungarian forces but was forced back by the German army. Additional fronts opened after the Ottoman Empire joined the war in 1914, Italy and Bulgaria
Kingdom of Bulgaria
The Kingdom of Bulgaria was established as an independent state when the Principality of Bulgaria, an Ottoman vassal, officially proclaimed itself independent on October 5, 1908 . This move also formalised the annexation of the Ottoman province of Eastern Rumelia, which had been under the control...

 in 1915 and Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

 in 1916. The Russian Empire collapsed in 1917, and Russia left the war after the October Revolution
October Revolution
The October Revolution , also known as the Great October Socialist Revolution , Red October, the October Uprising or the Bolshevik Revolution, was a political revolution and a part of the Russian Revolution of 1917...

 later that year. After a 1918 German offensive along the western front, United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 forces entered the trenches and the Allies drove back the German armies in a series of successful offensives. Germany, which had its own trouble with revolutionaries
German Revolution
The German Revolution was the politically-driven civil conflict in Germany at the end of World War I, which resulted in the replacement of Germany's imperial government with a republic...

 at this point, agreed to a cease-fire on 11 November 1918, later known as Armistice Day
Armistice Day
Armistice Day is on 11 November and commemorates the armistice signed between the Allies of World War I and Germany at Compiègne, France, for the cessation of hostilities on the Western Front of World War I, which took effect at eleven o'clock in the morning—the "eleventh hour of the eleventh day...

. The war had ended in victory of the Allies.

By the war's end, four major imperial powers—the German
German Empire
The German Empire refers to Germany during the "Second Reich" period from the unification of Germany and proclamation of Wilhelm I as German Emperor on 18 January 1871, to 1918, when it became a federal republic after defeat in World War I and the abdication of the Emperor, Wilhelm II.The German...

, Russian
Russian Empire
The Russian Empire was a state that existed from 1721 until the Russian Revolution of 1917. It was the successor to the Tsardom of Russia and the predecessor of the Soviet Union...

, Austro-Hungarian and Ottoman
Ottoman Empire
The Ottoman EmpireIt was usually referred to as the "Ottoman Empire", the "Turkish Empire", the "Ottoman Caliphate" or more commonly "Turkey" by its contemporaries...

 empires—had been militarily and politically defeated and ceased to exist. The successor states of the former two lost a great amount of territory, while the latter two were dismantled entirely. The map of central Europe was redrawn into several smaller states. The League of Nations
League of Nations
The League of Nations was an intergovernmental organization founded as a result of the Paris Peace Conference that ended the First World War. It was the first permanent international organization whose principal mission was to maintain world peace...

 was formed in the hope of preventing another such conflict. The European nationalism spawned by the war and the breakup of empires, the repercussions of Germany's defeat and problems with the Treaty of Versailles
Treaty of Versailles
The Treaty of Versailles was one of the peace treaties at the end of World War I. It ended the state of war between Germany and the Allied Powers. It was signed on 28 June 1919, exactly five years after the assassination of Archduke Franz Ferdinand. The other Central Powers on the German side of...

 are generally agreed to be factors contributing to World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

.

Etymology

During the Interwar period, the War was known by a variety of names in English-speaking countries. Besides being called the World War and the Great War, which were the most common names, it was also referred to merely as The War, or The War in Europe, the War of Nations, the 1914 War, or some variation on these and other names. Occasionally different names were used interchangeably within a single work, as in a Time article from 1924. After the onset of the Second World War in 1939, the terms World War I or the First World War became standard, with British and Canadian historians favouring the First World War and Americans World War I. The notion that the "World War" was merely the first in a series was not a new idea at the time, however; it was first introduced in September 1914 by German biologist and philosopher Ernst Haeckel
Ernst Haeckel
The "European War" became known as "The Great War", and it was not until 1920, in the book "The First World War 1914-1918" by Charles à Court Repington, that the term "First World War" was used as the official name for the conflict.-Research:...

, who claimed that "there is no doubt that the course and character of the feared 'European War' ... will become the first world war in the full sense of the word." The First World War was the title of a 1920 history by the officer and journalist Charles à Court Repington
Charles à Court Repington
Lieutenant Colonel Charles à Court Repington , CMG, was a British Army officer and war correspondent.-Biography:Charles Repington was born at Heytesbury, Wiltshire in 1858, where his father was a Conservative Party Member of Parliament...

.
In France and Belgium, the war was sometimes referred to as La Guerre du Droit (the War for Justice) or La Guerre Pour la Civilisation / de Oorlog tot de Beschaving (the War to Preserve Civilisation), especially on medals and commemorative monuments.

Background

In the 19th Century, the major European powers had gone to great lengths to maintain a balance of power
Balance of power in international relations
In international relations, a balance of power exists when there is parity or stability between competing forces. The concept describes a state of affairs in the international system and explains the behavior of states in that system...

 throughout Europe, resulting by 1900 in a complex network of political and military alliances throughout the continent. These had started in 1815, with the Holy Alliance
Holy Alliance
The Holy Alliance was a coalition of Russia, Austria and Prussia created in 1815 at the behest of Czar Alexander I of Russia, signed by the three powers in Paris on September 26, 1815, in the Congress of Vienna after the defeat of Napoleon.Ostensibly it was to instill the Christian values of...

 between Prussia
Prussia
Prussia was a German kingdom and historic state originating out of the Duchy of Prussia and the Margraviate of Brandenburg. For centuries, the House of Hohenzollern ruled Prussia, successfully expanding its size by way of an unusually well-organized and effective army. Prussia shaped the history...

, Russia, and Austria. Then, in October 1873, German Chancellor Bismarck
Otto von Bismarck
Otto Eduard Leopold, Prince of Bismarck, Duke of Lauenburg , simply known as Otto von Bismarck, was a Prussian-German statesman whose actions unified Germany, made it a major player in world affairs, and created a balance of power that kept Europe at peace after 1871.As Minister President of...

 negotiated the League of the Three Emperors
League of the Three Emperors
The League of the Three Emperors was an unstable alliance between Tsar Alexander II of Russia, Emperor Franz Joseph I of Austria-Hungary and Kaiser Wilhelm I of Germany.- Formation 1873 :...

 (German: Dreikaiserbund) between the monarchs of Austria–Hungary, Russia and Germany. This agreement failed because Austria–Hungary and Russia could not agree over Balkan policy, leaving Germany and Austria–Hungary in an alliance formed in 1879, called the Dual Alliance. This was seen as a method of countering Russian influence in the Balkans
Balkans
The Balkans is a geopolitical and cultural region of southeastern Europe...

 as the Ottoman Empire
Ottoman Empire
The Ottoman EmpireIt was usually referred to as the "Ottoman Empire", the "Turkish Empire", the "Ottoman Caliphate" or more commonly "Turkey" by its contemporaries...

 continued to weaken. In 1882, this alliance was expanded to include Italy in what became the Triple Alliance
Triple Alliance (1882)
The Triple Alliance was the military alliance between Germany, Austria–Hungary, and Italy, , that lasted from 1882 until the start of World War I in 1914...

.

After 1870, European conflict was averted largely through a carefully planned network of treaties between the German Empire and the remainder of Europe orchestrated by Bismarck. He especially worked to hold Russia at Germany's side to avoid a two-front war with France and Russia. When Wilhelm II ascended to the throne as German Emperor
German Emperor
This article is about the emperors of the German Empire. For full list of German monarchs before 1871, see List of German monarchs.The German Emperor was the official title of the Head of State and ruler of the German Empire, beginning with the proclamation of Wilhelm I as emperor during the...

 (Kaiser), Bismarck's alliances were gradually de-emphasised. For example, the Kaiser refused to renew the Reinsurance Treaty
Reinsurance Treaty
The Reinsurance Treaty of June 18, 1887 was an attempt by German Chancellor Otto von Bismarck to continue to ally with Russia after the League of the Three Emperors had broken down in the aftermath of the 1885 Serbo-Bulgarian War....

 with Russia in 1890. Two years later, the Franco-Russian Alliance
Franco-Russian Alliance
The Franco-Russian Alliance was a military alliance between the French Third Republic and the Russian Empire that ran from 1892 to 1917. The alliance ended the diplomatic isolation of France and undermined the supremacy of the German Empire in Europe...

 was signed to counteract the force of the Triple Alliance. In 1904, the United Kingdom sealed an alliance with France, the Entente Cordiale
Entente Cordiale
The Entente Cordiale was a series of agreements signed on 8 April 1904 between the United Kingdom and the French Republic. Beyond the immediate concerns of colonial expansion addressed by the agreement, the signing of the Entente Cordiale marked the end of almost a millennium of intermittent...

, and in 1907, the United Kingdom and Russia signed the Anglo-Russian Convention
Anglo-Russian Convention
The British-Russian Convention is a political convention of several days that took place between the Russian Empire and the United Kingdom of Great Britain and Ireland...

. This system of interlocking bilateral agreements formed the Triple Entente
Triple Entente
The Triple Entente was the name given to the alliance among Britain, France and Russia after the signing of the Anglo-Russian Entente in 1907....

.

German industrial and economic power had grown greatly after unification and the foundation of the Empire in 1870. From the mid-1890s on, the government of Wilhelm II used this base to devote significant economic resources to building up the Kaiserliche Marine
Kaiserliche Marine
The Imperial German Navy was the German Navy created at the time of the formation of the German Empire. It existed between 1871 and 1919, growing out of the small Prussian Navy and Norddeutsche Bundesmarine, which primarily had the mission of coastal defense. Kaiser Wilhelm II greatly expanded...

(Imperial German Navy), established by Admiral Alfred von Tirpitz
Alfred von Tirpitz
Alfred von Tirpitz was a German Admiral, Secretary of State of the German Imperial Naval Office, the powerful administrative branch of the German Imperial Navy from 1897 until 1916. Prussia never had a major navy, nor did the other German states before the German Empire was formed in 1871...

, in rivalry with the British Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 for world naval supremacy. As a result, each nation strove to out-build the other in terms of capital ships. With the launch of in 1906, the British Empire expanded on its significant advantage over its German rival. The arms race between Britain and Germany eventually extended to the rest of Europe, with all the major powers devoting their industrial base to producing the equipment and weapons necessary for a pan-European conflict. Between 1908 and 1913, the military spending of the European powers increased by 50 percent.
Austria-Hungary precipitated the Bosnian crisis
Bosnian crisis
The Bosnian Crisis of 1908–1909, also known as the Annexation crisis, or the First Balkan Crisis, erupted into public view when on 6 October 1908, Austria-Hungary announced the annexation of Bosnia and Herzegovina. Russia, the Ottoman Empire, Britain, Italy, Serbia, Montenegro, Germany and France...

 of 1908–1909 by officially annexing the former Ottoman territory of Bosnia and Herzegovina
Bosnia and Herzegovina
Bosnia and Herzegovina , sometimes called Bosnia-Herzegovina or simply Bosnia, is a country in Southern Europe, on the Balkan Peninsula. Bordered by Croatia to the north, west and south, Serbia to the east, and Montenegro to the southeast, Bosnia and Herzegovina is almost landlocked, except for the...

, which it had occupied since 1878. This angered the Kingdom of Serbia
Kingdom of Serbia
The Kingdom of Serbia was created when Prince Milan Obrenović, ruler of the Principality of Serbia, was crowned King in 1882. The Principality of Serbia was ruled by the Karađorđevic dynasty from 1817 onwards . The Principality, suzerain to the Porte, had expelled all Ottoman troops by 1867, de...

 and its patron, the Pan-Slavic
Pan-Slavism
Pan-Slavism was a movement in the mid-19th century aimed at unity of all the Slavic peoples. The main focus was in the Balkans where the South Slavs had been ruled for centuries by other empires, Byzantine Empire, Austria-Hungary, the Ottoman Empire, and Venice...

 and Orthodox
Eastern Orthodox Church
The Orthodox Church, officially called the Orthodox Catholic Church and commonly referred to as the Eastern Orthodox Church, is the second largest Christian denomination in the world, with an estimated 300 million adherents mainly in the countries of Belarus, Bulgaria, Cyprus, Georgia, Greece,...

 Russian Empire
Russian Empire
The Russian Empire was a state that existed from 1721 until the Russian Revolution of 1917. It was the successor to the Tsardom of Russia and the predecessor of the Soviet Union...

. Russian political manoeuvring in the region destabilised peace accords that were already fracturing in what was known as "the powder keg of Europe
Powder keg of Europe
The "Powder keg of Europe", sometimes alternately known as the "Balkan Powder Keg", refers to the Balkans in the early part of the 20th century. In this time period there were a number of overlapping claims to territories and spheres of influence between the major European powers such as Russia and...

".

In 1912 and 1913 the First Balkan War
First Balkan War
The First Balkan War, which lasted from October 1912 to May 1913, pitted the Balkan League against the Ottoman Empire. The combined armies of the Balkan states overcame the numerically inferior and strategically disadvantaged Ottoman armies and achieved rapid success...

 was fought between the Balkan League
Balkan League
The Balkan League was an alliance formed by a series of bilateral treaties concluded in 1912 between the Balkan states of Bulgaria, Greece, Montenegro and Serbia, and directed against the Ottoman Empire, which at the time still controlled much of the Balkan peninsula...

 and the fracturing Ottoman Empire. The resulting Treaty of London further shrank the Ottoman Empire, creating an independent Albanian State
Albania
Albania , officially known as the Republic of Albania , is a country in Southeastern Europe, in the Balkans region. It is bordered by Montenegro to the northwest, Kosovo to the northeast, the Republic of Macedonia to the east and Greece to the south and southeast. It has a coast on the Adriatic Sea...

 while enlarging the territorial holdings of Bulgaria, Serbia, Montenegro, and Greece. When Bulgaria attacked both Serbia and Greece on 16 June 1913, it lost most of Macedonia to Serbia and Greece and Southern Dobruja
Southern Dobruja
Southern Dobruja is an area of north-eastern Bulgaria comprising the administrative districts named for its two principal cities of Dobrich and Silistra...

 to Romania in the 33-day Second Balkan War
Second Balkan War
The Second Balkan War was a conflict which broke out when Bulgaria, dissatisfied with its share of the spoils of the First Balkan War, attacked its former allies, Serbia and Greece, on 29 June 1913. Bulgaria had a prewar agreement about the division of region of Macedonia...

, further destabilising the region.

On 28 June 1914, Gavrilo Princip
Gavrilo Princip
Gavrilo Princip was the Bosnian Serb who assassinated Archduke Franz Ferdinand of Austria and his wife, Sophie, Duchess of Hohenberg, in Sarajevo on 28 June 1914...

, a Bosnian-Serb student and member of Young Bosnia
Young Bosnia
Young Bosnia was a revolutionary movement active before World War I, the members were predominantly school students who were ethnic Serbs, but included Bosniaks...

, assassinated the heir to the Austro-Hungarian throne, Archduke Franz Ferdinand of Austria
Archduke Franz Ferdinand of Austria
Franz Ferdinand was an Archduke of Austria-Este, Austro-Hungarian and Royal Prince of Hungary and of Bohemia, and from 1889 until his death, heir presumptive to the Austro-Hungarian throne. His assassination in Sarajevo precipitated Austria-Hungary's declaration of war against Serbia...

 in Sarajevo
Sarajevo
Sarajevo |Bosnia]], surrounded by the Dinaric Alps and situated along the Miljacka River in the heart of Southeastern Europe and the Balkans....

, Bosnia. This began a period of diplomatic manoeuvring among Austria-Hungary, Germany, Russia, France, and Britain called the July Crisis. Wanting to finally end Serbian interference in Bosnia, Austria-Hungary delivered the July Ultimatum to Serbia, a series of ten demands intentionally made unacceptable, intending to provoke a war with Serbia. When Serbia agreed to only eight of the ten demands, Austria-Hungary declared war on 28 July 1914. Strachan
Hew Strachan
Brigadier Professor Hew Francis Anthony Strachan, DL, FRSE, FRHS is a Scottish military historian, well known for his work on the administration of the British Army and the history of the First World War...

 argues, "Whether an equivocal and early response by Serbia would have made any difference to Austria-Hungary's behaviour must be doubtful. Franz Ferdinand was not the sort of personality who commanded popularity, and his demise did not cast the empire into deepest mourning".

The Russian Empire, unwilling to allow Austria–Hungary to eliminate its influence in the Balkans, and in support of its longtime Serb protégés, ordered a partial mobilisation one day later. When the German Empire began to mobilise on 30 July 1914, France, resentful of the German conquest of Alsace-Lorraine
Alsace-Lorraine
The Imperial Territory of Alsace-Lorraine was a territory created by the German Empire in 1871 after it annexed most of Alsace and the Moselle region of Lorraine following its victory in the Franco-Prussian War. The Alsatian part lay in the Rhine Valley on the west bank of the Rhine River and east...

 during the Franco-Prussian War
Franco-Prussian War
The Franco-Prussian War or Franco-German War, often referred to in France as the 1870 War was a conflict between the Second French Empire and the Kingdom of Prussia. Prussia was aided by the North German Confederation, of which it was a member, and the South German states of Baden, Württemberg and...

, ordered French mobilisation on 1 August. Germany declared war on Russia on the same day. The United Kingdom declared war on Germany on 4 August 1914, following an "unsatisfactory reply" to the British ultimatum that Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

 must be kept neutral
Neutrality (international relations)
A neutral power in a particular war is a sovereign state which declares itself to be neutral towards the belligerents. A non-belligerent state does not need to be neutral. The rights and duties of a neutral power are defined in Sections 5 and 13 of the Hague Convention of 1907...

.

Confusion among the Central Powers

The strategy of the Central Powers suffered from miscommunication. Germany had promised to support Austria-Hungary's invasion of Serbia, but interpretations of what this meant differed. Previously-tested deployment plans had been replaced early in 1914, but the replacements had never been tested in exercises. Austro-Hungarian leaders believed Germany would cover its northern flank against Russia. Germany, however, envisioned Austria-Hungary directing most of its troops against Russia, while Germany dealt with France. This confusion forced the Austro-Hungarian Army
Austro-Hungarian Army
The Austro-Hungarian Army was the ground force of the Austro-Hungarian Dual Monarchy from 1867 to 1918. It was composed of three parts: the joint army , the Austrian Landwehr , and the Hungarian Honvédség .In the wake of fighting between the...

 to divide its forces between the Russian and Serbian fronts.

On 9 September 1914, the Septemberprogramm
Septemberprogramm
The Septemberprogramm was a plan drafted by the German leadership in the early weeks of the First World War. It detailed Germany's ambitious gains should it win the war, as it expected...

, a possible plan which detailed Germany's specific war aims and the conditions that Germany sought to force on the Allied Powers, was outlined by German Chancellor
Chancellor of Germany
The Chancellor of Germany is, under the German 1949 constitution, the head of government of Germany...

 Theobald von Bethmann-Hollweg
Theobald von Bethmann-Hollweg
Theobald von Bethmann Hollweg was a German politician and statesman who served as Chancellor of the German Empire from 1909 to 1917.-Origins:...

. It was never officially adopted.

African campaigns


Some of the first clashes of the war involved British, French, and German colonial forces in Africa. On 7 August, French and British troops invaded the German protectorate of Togoland
Togoland
Togoland was a German protectorate in West Africa from 1884 to 1914, encompassing what is now the nation of Togo and most of what is now the Volta Region of Ghana. The colony was established during the period generally known as the "Scramble for Africa"...

. On 10 August, German forces in South-West Africa
German South-West Africa
German South West Africa was a colony of Germany from 1884 until 1915, when it was taken over by South Africa and administered as South West Africa, finally becoming Namibia in 1990...

 attacked South Africa; sporadic and fierce fighting continued for the rest of the war. The German colonial forces in German East Africa
German East Africa
German East Africa was a German colony in East Africa, which included what are now :Burundi, :Rwanda and Tanganyika . Its area was , nearly three times the size of Germany today....

, led by Colonel Paul Emil von Lettow-Vorbeck
Paul Emil von Lettow-Vorbeck
Paul Emil von Lettow-Vorbeck was a general in the Imperial German Army and the commander of the German East Africa campaign. For four years, with a force that never exceeded about 14,000 , he held in check a much larger force of 300,000 British, Belgian, and Portuguese troops...

, fought a guerrilla warfare
Guerrilla warfare
Guerrilla warfare is a form of irregular warfare and refers to conflicts in which a small group of combatants including, but not limited to, armed civilians use military tactics, such as ambushes, sabotage, raids, the element of surprise, and extraordinary mobility to harass a larger and...

 campaign during World War I and only surrendered two weeks after the armistice took effect in Europe.

Serbian campaign

The Serbian army fought the Battle of Cer
Battle of Cer
The Battle of Cer also known as Battle of Jadar was one of the first battles of World War I, it also marked the first Allied victory in the war. The battle was fought between the Austro-Hungarian Army and Serbian forces. The results improved Serbian standing in the Alliance...

 against the invading Austro-Hungarians, beginning on 12 August, occupying defensive positions on the south side of the Drina
Drina
The Drina is a 346 kilometer long river, which forms most of the border between Bosnia and Herzegovina and Serbia. It is the longest tributary of the Sava River and the longest karst river in the Dinaric Alps which belongs to the Danube river watershed...

 and Sava rivers. Over the next two weeks Austrian attacks were thrown back with heavy losses, which marked the first major Allied victory of the war and dashed Austro-Hungarian hopes of a swift victory. As a result, Austria had to keep sizeable forces on the Serbian front, weakening its efforts against Russia.

German forces in Belgium and France


At the outbreak of the First World War, the German army (consisting in the West of seven field armies
German Army order of battle (1914)
This is the German Army order of battle on the outbreak of war in August 1914.-GHQ:The overall commander of the Imperial German Army was Kaiser Wilhelm II. The Chief of the General Staff was Generaloberst Helmuth von Moltke the Younger, with General von Stein as Deputy Chief...

) carried out a modified version of the Schlieffen Plan
Schlieffen Plan
The Schlieffen Plan was the German General Staff's early 20th century overall strategic plan for victory in a possible future war in which the German Empire might find itself fighting on two fronts: France to the west and Russia to the east...

, designed to quickly attack France through neutral Belgium before turning southwards to encircle the French army on the German border. The plan called for the right flank of the German advance to converge on Paris, and initially the Germans were successful, particularly in the Battle of the Frontiers
Battle of the Frontiers
The Battle of the Frontiers was a series of battles fought along the eastern frontier of France and in southern Belgium shortly after the outbreak of World War I. The battles represented a collision between the military strategies of the French Plan XVII and the German Schlieffen Plan...

 (14–24 August). By 12 September, the French, with assistance from the British forces, halted the German advance east of Paris at the First Battle of the Marne
First Battle of the Marne
The Battle of the Marne was a First World War battle fought between 5 and 12 September 1914. It resulted in an Allied victory against the German Army under Chief of Staff Helmuth von Moltke the Younger. The battle effectively ended the month long German offensive that opened the war and had...

 (5–12 September). The last days of this battle signified the end of mobile warfare in the west. The French offensive into Germany, launched on 7 August with the Battle of Mulhouse
Battle of Mulhouse
The Battle of Mulhouse , which began on August 9, 1914, was the opening attack of World War I by the French army against Germany...

, had limited success.

In the east, only one field army defended East Prussia
East Prussia
East Prussia is the main part of the region of Prussia along the southeastern Baltic Coast from the 13th century to the end of World War II in May 1945. From 1772–1829 and 1878–1945, the Province of East Prussia was part of the German state of Prussia. The capital city was Königsberg.East Prussia...

, and when Russia attacked in this region it diverted German forces intended for the Western Front. Germany defeated Russia in a series of battles collectively known as the First Battle of Tannenberg
Battle of Tannenberg (1914)
The Battle of Tannenberg was an engagement between the Russian Empire and the German Empire in the first days of World War I. It was fought by the Russian First and Second Armies against the German Eighth Army between 23 August and 30 August 1914. The battle resulted in the almost complete...

 (17 August – 2 September), but this diversion aggravated problems of insufficient speed of advance from rail-heads not foreseen by the German General Staff
German General Staff
The German General Staff was an institution whose rise and development gave the German armed forces a decided advantage over its adversaries. The Staff amounted to its best "weapon" for nearly a century and a half....

. The Central Powers were denied a quick victory and forced to fight a war on two fronts. The German army had fought its way into a good defensive position inside France and had permanently incapacitated 230,000 more French and British troops than it had lost itself. Despite this, communications problems and questionable command decisions cost Germany the chance of early victory.

Asia and the Pacific

New Zealand occupied
Occupation of German Samoa
The Occupation of Samoa was the takeover and subsequent administration of the Pacific colony of German Samoa in August 1914 by an expeditionary force from New Zealand called the Samoa Expeditionary Force and New Zealand's first action in World War I...

 German Samoa
German Samoa
German Samoa was a German protectorate from 1900 to 1914, consisting of the islands of Upolu, Savai'i, Apolima and Manono, now wholly within the independent state Samoa, formerly Western Samoa...

 (later Western Samoa) on 30 August. On 11 September, the Australian Naval and Military Expeditionary Force
Australian Naval and Military Expeditionary Force
The Australian Naval and Military Expeditionary Force was a small volunteer force of approximately 2,000 men, raised in Australia shortly after the outbreak of the First World War to seize and destroy German wireless stations in German New Guinea in the south-west Pacific...

 landed on the island of Neu Pommern
New Britain
New Britain, or Niu Briten, is the largest island in the Bismarck Archipelago of Papua New Guinea. It is separated from the island of New Guinea by the Dampier and Vitiaz Straits and from New Ireland by St. George's Channel...

 (later New Britain), which formed part of German New Guinea
German New Guinea
German New Guinea was the first part of the German colonial empire. It was a protectorate from 1884 until 1914 when it fell to Australia following the outbreak of the First World War. It consisted of the northeastern part of New Guinea and several nearby island groups...

. Japan seized Germany's Micronesia
Micronesia
Micronesia is a subregion of Oceania, comprising thousands of small islands in the western Pacific Ocean. It is distinct from Melanesia to the south, and Polynesia to the east. The Philippines lie to the west, and Indonesia to the southwest....

n colonies and, after the Siege of Tsingtao, the German coaling port of Qingdao
Qingdao
' also known in the West by its postal map spelling Tsingtao, is a major city with a population of over 8.715 million in eastern Shandong province, Eastern China. Its built up area, made of 7 urban districts plus Jimo city, is home to about 4,346,000 inhabitants in 2010.It borders Yantai to the...

 in the Chinese Shandong
Shandong
' is a Province located on the eastern coast of the People's Republic of China. Shandong has played a major role in Chinese history from the beginning of Chinese civilization along the lower reaches of the Yellow River and served as a pivotal cultural and religious site for Taoism, Chinese...

 peninsula. Within a few months, the Allied forces had seized all the German territories in the Pacific; only isolated commerce raiders and a few holdouts in New Guinea remained.

Trench warfare begins

Military tactics before World War I had failed to keep pace with advances in technology. These advances allowed for impressive defence systems, which out-of-date military tactics could not break through for most of the war. Barbed wire
Barbed wire
Barbed wire, also known as barb wire , is a type of fencing wire constructed with sharp edges or points arranged at intervals along the strand. It is used to construct inexpensive fences and is used atop walls surrounding secured property...

 was a significant hindrance to massed infantry advances. Artillery
Artillery
Originally applied to any group of infantry primarily armed with projectile weapons, artillery has over time become limited in meaning to refer only to those engines of war that operate by projection of munitions far beyond the range of effect of personal weapons...

, vastly more lethal than in the 1870s, coupled with machine guns, made crossing open ground extremely difficult. The Germans introduced poison gas
Poison gas in World War I
The use of chemical weapons in World War I ranged from disabling chemicals, such as tear gas and the severe mustard gas, to lethal agents like phosgene and chlorine. This chemical warfare was a major component of the first global war and first total war of the 20th century. The killing capacity of...

; it soon became used by both sides, though it never proved decisive in winning a battle. Its effects were brutal, causing slow and painful death, and poison gas became one of the most-feared and best-remembered horrors of the war. Commanders on both sides failed to develop tactics for breaching entrenched positions without heavy casualties.

In time, however, technology began to produce new offensive weapons, such as the tank
Tank
A tank is a tracked, armoured fighting vehicle designed for front-line combat which combines operational mobility, tactical offensive, and defensive capabilities...

. Britain and France were its primary users; the Germans employed captured Allied tanks and small numbers of their own design. After the First Battle of the Marne
First Battle of the Marne
The Battle of the Marne was a First World War battle fought between 5 and 12 September 1914. It resulted in an Allied victory against the German Army under Chief of Staff Helmuth von Moltke the Younger. The battle effectively ended the month long German offensive that opened the war and had...

, both Entente
Triple Entente
The Triple Entente was the name given to the alliance among Britain, France and Russia after the signing of the Anglo-Russian Entente in 1907....

 and German forces began a series of outflanking manoeuvres, in the so-called "Race to the Sea
Race to the Sea
The Race to the Sea is a name given to the period early in the First World War when the two sides were still engaged in mobile warfare on the Western Front. With the German advance stalled at the First Battle of the Marne, the opponents continually attempted to outflank each other through...

". Britain and France soon found themselves facing entrenched German forces from Lorraine
Lorraine (province)
The Duchy of Upper Lorraine was an historical duchy roughly corresponding with the present-day northeastern Lorraine region of France, including parts of modern Luxembourg and Germany. The main cities were Metz, Verdun, and the historic capital Nancy....

 to Belgium's coast. Britain and France sought to take the offensive, while Germany defended the occupied territories; consequently, German trenches were much better constructed than those of their enemy. Anglo-French trenches were only intended to be "temporary" before their forces broke through German defences. Both sides tried to break the stalemate using scientific and technological advances. On 22 April 1915 at the Second Battle of Ypres
Second Battle of Ypres
The Second Battle of Ypres was the first time Germany used poison gas on a large scale on the Western Front in the First World War and the first time a former colonial force pushed back a major European power on European soil, which occurred in the battle of St...

, the Germans (violating the Hague Convention
Hague Conventions (1899 and 1907)
The Hague Conventions were two international treaties negotiated at international peace conferences at The Hague in the Netherlands: The First Hague Conference in 1899 and the Second Hague Conference in 1907...

) used chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...

 gas for the first time on the Western Front. Algerian troops retreated when gassed and a six-kilometre (four-mile) hole opened in the Allied lines that the Germans quickly exploited, taking Kitcheners' Wood. Canadian soldiers closed the breach at the Second Battle of Ypres
Second Battle of Ypres
The Second Battle of Ypres was the first time Germany used poison gas on a large scale on the Western Front in the First World War and the first time a former colonial force pushed back a major European power on European soil, which occurred in the battle of St...

. At the Third Battle of Ypres, Canadian and ANZAC troops took the village of Passchendaele.
On 1 July 1916, the British Army
British Army
The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...

 endured the bloodiest day in its history, suffering 57,470 casualties, including 19,240 dead, on the first day
First day on the Somme
The first day on the Somme, 1 July 1916, was the opening day of the Battle of Albert, which was the first phase of the British and French offensive that became known as the Battle of the Somme...

 of the Battle of the Somme. Most of the casualties occurred in the first hour of the attack. The entire Somme offensive cost the British Army almost half a million men.

Neither side proved able to deliver a decisive blow for the next two years, though protracted German action at Verdun
Battle of Verdun
The Battle of Verdun was one of the major battles during the First World War on the Western Front. It was fought between the German and French armies, from 21 February – 18 December 1916, on hilly terrain north of the city of Verdun-sur-Meuse in north-eastern France...

 throughout 1916, combined with the bloodletting at the Somme, brought the exhausted French army to the brink of collapse. Futile attempts at frontal assault came at a high price for both the British and the French poilu
Poilu
Poilu is a warmly informal term for a French World War I infantryman, meaning, literally, hairy one. The term came into popular usage in France during the era of Napoleon Bonaparte and his massive citizen armies, though the term grognard was also common. It is still widely used as a term of...

(infantry) and led to widespread mutinies
French Army Mutinies (1917)
The French Army Mutinies of 1917 took place amongst the French troops on the Western Front in Northern France. They started just after the conclusion of the disastrous Second Battle of the Aisne, the main action in the Nivelle Offensive, and involved, to various degrees, nearly half of the French...

, especially during the Nivelle Offensive
Nivelle offensive
The Nivelle Offensive was a 1917 French attack on the Western Front in the First World War. Promised as the assault that would end the war within 48 hours, with casualties expected of around 10,000 men, it failed on both counts. It was a three-stage plan:...

.
Throughout 1915–17, the British Empire and France suffered more casualties than Germany, because of both the strategic and tactical stances chosen by the sides. Strategically, while the Germans only mounted a single main offensive at Verdun
Battle of Verdun
The Battle of Verdun was one of the major battles during the First World War on the Western Front. It was fought between the German and French armies, from 21 February – 18 December 1916, on hilly terrain north of the city of Verdun-sur-Meuse in north-eastern France...

, the Allies made several attempts to break through German lines. Tactically, German commander Erich Ludendorff
Erich Ludendorff
Erich Friedrich Wilhelm Ludendorff was a German general, victor of Liège and of the Battle of Tannenberg...

's doctrine of "elastic defence" was well suited for trench warfare. This defence had a lightly defended forward position and a more powerful main position farther back beyond artillery range, from which an immediate and powerful counter-offensive could be launched.

Ludendorff wrote on the fighting in 1917,

On the battle of the Menin Road Ridge, Ludendorff wrote,

Around 1.1 to 1.2 million soldiers from the British and Dominion armies were on the Western Front at any one time. A thousand battalions, occupying sectors of the line from the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...

 to the Orne River
Orne River (Lorraine)
The Orne is a river in Lorraine, north-eastern France, which is a left tributary of the Moselle and sub-tributary of the Rhine. Its source is in the hills northeast of Verdun...

, operated on a month-long four-stage rotation system, unless an offensive was underway. The front contained over 9600 kilometres (5,965 mi) of trenches. Each battalion held its sector for about a week before moving back to support lines and then further back to the reserve lines before a week out-of-line, often in the Poperinge
Poperinge
Poperinge is a municipality located in the Belgian province of West Flanders, Flemish Region, and has a history going back to mediaeval times. The municipality comprises the town of Poperinge proper and surrounding villages. The area is famous for its hops and lace.-The town:Poperinge is situated...

 or Amiens
Amiens
Amiens is a city and commune in northern France, north of Paris and south-west of Lille. It is the capital of the Somme department in Picardy...

 areas.

In the 1917 Battle of Arras
Battle of Arras (1917)
The Battle of Arras was a British offensive during the First World War. From 9 April to 16 May 1917, British, Canadian, New Zealand, Newfoundland, and Australian troops attacked German trenches near the French city of Arras on the Western Front....

, the only significant British military success was the capture of Vimy Ridge by the Canadian Corps
Canadian Corps
The Canadian Corps was a World War I corps formed from the Canadian Expeditionary Force in September 1915 after the arrival of the 2nd Canadian Division in France. The corps was expanded by the addition of the 3rd Canadian Division in December 1915 and the 4th Canadian Division in August 1916...

 under Sir Arthur Currie and Julian Byng. The assaulting troops could, for the first time, overrun, rapidly reinforce and hold the ridge defending the coal-rich Douai
Douai
-Main sights:Douai's ornate Gothic style belfry was begun in 1380, on the site of an earlier tower. The 80 m high structure includes an impressive carillon, consisting of 62 bells spanning 5 octaves. The originals, some dating from 1391 were removed in 1917 during World War I by the occupying...

 plain.

Naval war

At the start of the war, the German Empire had cruiser
Cruiser
A cruiser is a type of warship. The term has been in use for several hundreds of years, and has had different meanings throughout this period...

s scattered across the globe, some of which were subsequently used to attack Allied merchant shipping. The British Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 systematically hunted them down, though not without some embarrassment from its inability to protect Allied shipping. For example, the German detached light cruiser SMS Emden, part of the East-Asia squadron stationed at Tsingtao, seized or destroyed 15 merchantmen, as well as sinking a Russian cruiser and a French destroyer. However, most of the German East-Asia squadron
German East Asia Squadron
The German East Asia Squadron was a German Navy cruiser squadron which operated mainly in the Pacific Ocean between the 1870s and 1914...

—consisting of the armoured cruisers and , light cruisers and and two transport ships—did not have orders to raid shipping and was instead underway to Germany when it met British warships. The German flotilla and sank two armoured cruisers at the Battle of Coronel
Battle of Coronel
The First World War naval Battle of Coronel took place on 1 November 1914 off the coast of central Chile near the city of Coronel. German Kaiserliche Marine forces led by Vice-Admiral Graf Maximilian von Spee met and defeated a Royal Navy squadron commanded by Rear-Admiral Sir Christopher...

, but was almost destroyed at the Battle of the Falkland Islands
Battle of the Falkland Islands
The Battle of the Falkland Islands was a British naval victory over the Imperial German Navy on 8 December 1914 during the First World War in the South Atlantic...

 in December 1914, with only Dresden and a few auxiliaries escaping, but at the Battle of Más a Tierra
Battle of Más a Tierra
The Battle of Más a Tierra was a First World War battle fought on 14 March 1915, near the Chilean island of Más a Tierra, between a British squadron and a German light cruiser...

 these too were destroyed or interned.

Soon after the outbreak of hostilities, Britain began a naval blockade of Germany
Blockade of Germany
The Blockade of Germany, or the Blockade of Europe, occurred from 1914-1919 and was a prolonged naval operation conducted by the Allied Powers during and after World War I in an effort to restrict the maritime supply of raw materials and foodstuffs to the Central Powers, which included Germany,...

. The strategy proved effective, cutting off vital military and civilian supplies, although this blockade violated accepted international law codified by several international agreements of the past two centuries. Britain mined international waters to prevent any ships from entering entire sections of ocean, causing danger to even neutral ships. Since there was limited response to this tactic, Germany expected a similar response to its unrestricted submarine warfare.

The 1916 Battle of Jutland
Battle of Jutland
The Battle of Jutland was a naval battle between the British Royal Navy's Grand Fleet and the Imperial German Navy's High Seas Fleet during the First World War. The battle was fought on 31 May and 1 June 1916 in the North Sea near Jutland, Denmark. It was the largest naval battle and the only...

 (German: Skagerrakschlacht, or "Battle of the Skagerrak") developed into the largest naval battle of the war, the only full-scale clash of battleships during the war, and one of the largest in history. It took place on 31 May – 1 June 1916, in the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...

 off Jutland
Jutland
Jutland , historically also called Cimbria, is the name of the peninsula that juts out in Northern Europe toward the rest of Scandinavia, forming the mainland part of Denmark. It has the North Sea to its west, Kattegat and Skagerrak to its north, the Baltic Sea to its east, and the Danish–German...

. The Kaiserliche Marine's High Seas Fleet, commanded by Vice Admiral Reinhard Scheer
Reinhard Scheer
Reinhard Scheer was an Admiral in the German Kaiserliche Marine. Scheer joined the navy in 1879 as an officer cadet; he progressed through the ranks, commanding cruisers and battleships, as well as major staff positions on land. At the outbreak of World War I, Scheer was the commander of the II...

, squared off against the Royal Navy's Grand Fleet, led by Admiral Sir John Jellicoe
John Jellicoe, 1st Earl Jellicoe
Admiral of the Fleet John Rushworth Jellicoe, 1st Earl Jellicoe, GCB, OM, GCVO was a British Royal Navy admiral who commanded the Grand Fleet at the Battle of Jutland in World War I...

. The engagement was a stand off, as the Germans, outmanoeuvred by the larger British fleet, managed to escape and inflicted more damage to the British fleet than they received. Strategically, however, the British asserted their control of the sea, and the bulk of the German surface fleet remained confined to port for the duration of the war.

German U-boats attempted to cut the supply lines between North America and Britain. The nature of submarine warfare meant that attacks often came without warning, giving the crews of the merchant ships little hope of survival. The United States launched a protest, and Germany changed its rules of engagement. After the notorious sinking of the passenger ship RMS Lusitania
RMS Lusitania
RMS Lusitania was a British ocean liner designed by Leonard Peskett and built by John Brown and Company of Clydebank, Scotland. The ship entered passenger service with the Cunard Line on 26 August 1907 and continued on the line's heavily-traveled passenger service between Liverpool, England and New...

 in 1915, Germany promised not to target passenger liners, while Britain armed its merchant ships, placing them beyond the protection of the "cruiser rules" which demanded warning and placing crews in "a place of safety" (a standard which lifeboats did not meet). Finally, in early 1917 Germany adopted a policy of unrestricted submarine warfare
Unrestricted submarine warfare
Unrestricted submarine warfare is a type of naval warfare in which submarines sink merchantmen without warning, as opposed to attacks per prize rules...

, realising the Americans would eventually enter the war. Germany sought to strangle Allied sea lanes before the U.S. could transport a large army overseas, but could maintain only five long-range U-boats on station, to limited effect.

The U-boat threat lessened in 1917, when merchant ships began travelling in convoys
Convoys in World War I
The convoy—a group of merchantmen or troopships travelling together with a naval escort—was revived during World War I , after having been discarded at the start of the Age of Steam...

, escorted by destroyer
Destroyer
In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...

s. This tactic made it difficult for U-boats to find targets, which significantly lessened losses; after the hydrophone
Hydrophone
A hydrophone is a microphone designed to be used underwater for recording or listening to underwater sound. Most hydrophones are based on a piezoelectric transducer that generates electricity when subjected to a pressure change...

 and depth charge
Depth charge
A depth charge is an anti-submarine warfare weapon intended to destroy or cripple a target submarine by the shock of exploding near it. Most use explosives and a fuze set to go off at a preselected depth in the ocean. Depth charges can be dropped by either surface ships, patrol aircraft, or from...

s were introduced, accompanying destroyers might attack a submerged submarine with some hope of success. Convoys slowed the flow of supplies, since ships had to wait as convoys were assembled. The solution to the delays was an extensive program to build new freighters. Troopships were too fast for the submarines and did not travel the North Atlantic in convoys. The U-boats had sunk more than 5,000 Allied ships, at a cost of 199 submarines.

World War I also saw the first use of aircraft carrier
Aircraft carrier
An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...

s in combat, with HMS Furious
HMS Furious (47)
HMS Furious was a modified cruiser built for the Royal Navy during the First World War. Designed to support the Baltic Project championed by the First Sea Lord of the Admiralty, Lord John Fisher, they were very lightly armoured and armed with only a few heavy guns. Furious was modified while...

 launching Sopwith Camels in a successful raid against the Zeppelin
Zeppelin
A Zeppelin is a type of rigid airship pioneered by the German Count Ferdinand von Zeppelin in the early 20th century. It was based on designs he had outlined in 1874 and detailed in 1893. His plans were reviewed by committee in 1894 and patented in the United States on 14 March 1899...

 hangars at Tondern
Tondern raid
The Tondern raid, officially designated Operation F.7, was a British bombing raid mounted by the Royal Navy and Royal Air Force against the Imperial German Navy's airship base at Tondern in Germany. It was the first attack in history made by aircraft flying from a carrier flight deck. On 19 July...

 in July 1918, as well as blimp
Blimp
A blimp, or non-rigid airship, is a floating airship without an internal supporting framework or keel. A non-rigid airship differs from a semi-rigid airship and a rigid airship in that it does not have any rigid structure, neither a complete framework nor a partial keel, to help the airbag...

s for antisubmarine patrol.

War in the Balkans

Faced with Russia, Austria-Hungary could spare only one-third of its army to attack Serbia. After suffering heavy losses, the Austrians briefly occupied the Serbian capital, Belgrade
Belgrade
Belgrade is the capital and largest city of Serbia. It is located at the confluence of the Sava and Danube rivers, where the Pannonian Plain meets the Balkans. According to official results of Census 2011, the city has a population of 1,639,121. It is one of the 15 largest cities in Europe...

. A Serbian counter attack in the battle of Kolubara
Battle of Kolubara
The Battle of Kolubara was a major victory of Serbia over the invading Austro-Hungarian armies during World War I. The invaders were routed, and driven back across the Serbian border....

, however, succeeded in driving them from the country by the end of 1914. For the first ten months of 1915, Austria-Hungary used most of its military reserves to fight Italy. German and Austro-Hungarian diplomats, however, scored a coup by persuading Bulgaria
Bulgaria
Bulgaria , officially the Republic of Bulgaria , is a parliamentary democracy within a unitary constitutional republic in Southeast Europe. The country borders Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, as well as the Black Sea to the east...

 to join in attacking Serbia. The Austro-Hungarian provinces of Slovenia
Slovenia
Slovenia , officially the Republic of Slovenia , is a country in Central and Southeastern Europe touching the Alps and bordering the Mediterranean. Slovenia borders Italy to the west, Croatia to the south and east, Hungary to the northeast, and Austria to the north, and also has a small portion of...

, Croatia
Croatia
Croatia , officially the Republic of Croatia , is a unitary democratic parliamentary republic in Europe at the crossroads of the Mitteleuropa, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers ...

 and Bosnia
Bosnia (region)
Bosnia is a eponomous region of Bosnia and Herzegovina. It lies mainly in the Dinaric Alps, ranging to the southern borders of the Pannonian plain, with the rivers Sava and Drina marking its northern and eastern borders. The other eponomous region, the southern, other half of the country is...

 provided troops for Austria-Hungary, invading Serbia as well as fighting Russia and Italy. Montenegro
Montenegro
Montenegro Montenegrin: Crna Gora Црна Гора , meaning "Black Mountain") is a country located in Southeastern Europe. It has a coast on the Adriatic Sea to the south-west and is bordered by Croatia to the west, Bosnia and Herzegovina to the northwest, Serbia to the northeast and Albania to the...

 allied itself with Serbia.

Serbia was conquered in a little more than a month. The attack began in October, when the Central Powers launched an offensive from the north; four days later the Bulgarians joined the attack from the east. The Serbian army, fighting on two fronts and facing certain defeat, retreated into Albania
Albania
Albania , officially known as the Republic of Albania , is a country in Southeastern Europe, in the Balkans region. It is bordered by Montenegro to the northwest, Kosovo to the northeast, the Republic of Macedonia to the east and Greece to the south and southeast. It has a coast on the Adriatic Sea...

, halting only once to make a stand against the Bulgarians. The Serbs suffered defeat near modern day Gnjilane
Gnjilane
Gnjilane or Gjilan is a city and municipality in eastern Kosovo. It is the administrative center of the District of Gjilan. It is famous for having been recorded the lowest temperature in Kosovo with on 25 January 1963.-Name and history:...

 in the Battle of Kosovo
Battle of Kosovo (1915)
The Kosovo Offensive Operation , the third major battle in history to have been fought there, occurred between 10 November 1915 and 4 December 1915.-Battle and Serbian defeat:...

. Montenegro covered the Serbian retreat towards the Adriatic coast in the Battle of Mojkovac
Battle of Mojkovac
The Battle of Mojkovac was a famous World War I battle fought between 6 January and 7 January 1916 near Mojkovac, Montenegro, between the armies of Austria-Hungary and Montenegro...

 in 6–7 January 1916, but ultimately the Austrians conquered Montenegro, too. Serbian forces were evacuated by ship to Greece.

In late 1915, a Franco-British force landed at Salonica in Greece, to offer assistance and to pressure the government to declare war against the Central Powers. Unfortunately for the Allies, the pro-German King Constantine I
Constantine I of Greece
Constantine I was King of Greece from 1913 to 1917 and from 1920 to 1922. He was commander-in-chief of the Hellenic Army during the unsuccessful Greco-Turkish War of 1897 and led the Greek forces during the successful Balkan Wars of 1912–1913, in which Greece won Thessaloniki and doubled in...

 dismissed the pro-Allied government of Eleftherios Venizelos
Eleftherios Venizelos
Eleftherios Venizelos was an eminent Greek revolutionary, a prominent and illustrious statesman as well as a charismatic leader in the early 20th century. Elected several times as Prime Minister of Greece and served from 1910 to 1920 and from 1928 to 1932...

, before the Allied expeditionary force could arrive. The friction between the king of Greece and the Allies continued to accumulate with the National Schism, which effectively divided Greece between regions still loyal to the king and the new provisional government of Venizelos in Salonica. After intensive diplomatic negotiations and an armed confrontation in Athens
Athens
Athens , is the capital and largest city of Greece. Athens dominates the Attica region and is one of the world's oldest cities, as its recorded history spans around 3,400 years. Classical Athens was a powerful city-state...

 between Allied and royalist forces (an incident known as Noemvriana
Noemvriana
The Noemvriana of November–December 1916 was a political dispute, which led to an armed confrontation in Athens between the royalist government of Greece and the Allies forces over the issue of Greece's neutrality during World War I....

) the king of Greece resigned, and his second son Alexander
Alexander of Greece
Alexander reigned as King of Greece from 1917 to 1920 until his unusual death as the result of sepsis contracted by being bitten by two monkeys.-Early life:...

 took his place. Venizelos returned to Athens on 29 May 1917 and Greece, now unified, officially joined the war on the side of the Allies. The entire Greek army was mobilized and began to participate in military operations against the Central Powers
Central Powers
The Central Powers were one of the two warring factions in World War I , composed of the German Empire, the Austro-Hungarian Empire, the Ottoman Empire, and the Kingdom of Bulgaria...

 on the Macedonian front.

After conquest, Serbia was divided between Austro-Hungary and Bulgaria. In 1917 the Serbs launched the Toplica Uprising and liberated for a short time the area between the Kopaonik
Kopaonik
Kopaonik ; is one of the larger mountain ranges of Serbia. It is located in the central part of Serbia, while a small portion extendeds to North Kosovo. Its highest point, Pančić's Peak, is above sea level....

 mountains and the South Morava river. The uprising was crushed by joint efforts of Bulgarian and Austrian forces at the end of March 1917.

The Macedonian Front was mostly static. French and Serbian forces retook limited areas of Macedonia by recapturing Bitola
Bitola
Bitola is a city in the southwestern part of the Republic of Macedonia. The city is an administrative, cultural, industrial, commercial, and educational centre. It is located in the southern part of the Pelagonia valley, surrounded by the Baba and Nidže mountains, 14 km north of the...

 on 19 November 1916 as a result of the costly Monastir Offensive
Monastir Offensive
Monastir Offensive was an Allied military operation against the forces of the Central Powers during World War I, intended to break the deadlock on the Macedonian Front by forcing the capitulation of Bulgaria and relieving the pressure on Romania. The offensive took the shape of a large battle and...

 which brought stabilization of the front. Only at the end of the conflict did the Entente powers break through, after most of the German and Austro-Hungarian troops had withdrawn. The Bulgarians suffered their only defeat of the war at the Battle of Dobro Pole
Battle of Dobro Pole
The Battle of Dobro Pole was a World War I battle, fought on 15 September 1918. The battle resulted in a decisive Entente victory, with a defeated Bulgaria left to sign an armistice, which removed it from World War I....

 but days later, they decisively defeated British and Greek forces at the Battle of Doiran
Battle of Doiran
The third Battle of Doiran was fought from 18 September to 19 September 1918, with the Greeks and the British assaulting the positions of the Bulgarian First Army near Dojran Lake. The battle was part of World War I and took place in the Balkan Theatre...

, avoiding occupation. Bulgaria signed an armistice on 29 September 1918. Hindenburg and Ludendorff concluded that the strategic and operational balance had now shifted decidedly against the Central Powers
Central Powers
The Central Powers were one of the two warring factions in World War I , composed of the German Empire, the Austro-Hungarian Empire, the Ottoman Empire, and the Kingdom of Bulgaria...

 and a day after the Bulgarian collapse, during a meeting with government officials, insisted on an immediate peace settlement.

The disappearance of the Macedonian front meant that the road to Budapest
Budapest
Budapest is the capital of Hungary. As the largest city of Hungary, it is the country's principal political, cultural, commercial, industrial, and transportation centre. In 2011, Budapest had 1,733,685 inhabitants, down from its 1989 peak of 2,113,645 due to suburbanization. The Budapest Commuter...

 and Vienna
Vienna
Vienna is the capital and largest city of the Republic of Austria and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.723 million , and is by far the largest city in Austria, as well as its cultural, economic, and political centre...

 was now opened for the 670,000-strong army of general Franchet d'Esperey as the Bulgarian surrender deprived the Central Powers
Central Powers
The Central Powers were one of the two warring factions in World War I , composed of the German Empire, the Austro-Hungarian Empire, the Ottoman Empire, and the Kingdom of Bulgaria...

 of the 278 infantry battalions and 1,500 guns (the equivalent of some 25 to 30 German divisions) that were previously holding the line. The German high command responded by sending only seven infantry and one cavalry division but these forces were far from enough for a front to be reestablished.

Ottoman Empire

The Ottoman Empire joined the Central Powers in the war, the secret Ottoman-German Alliance
Ottoman-German Alliance
The Ottoman–German Alliance was established between the Ottoman Empire and the German Empire on August 2, 1914. It was this binding alliance that ultimately led the Ottoman Empire to enter the First World War on the side of the Central Powers....

 having been signed in August 1914. It threatened Russia's Caucasian
Caucasus
The Caucasus, also Caucas or Caucasia , is a geopolitical region at the border of Europe and Asia, and situated between the Black and the Caspian sea...

 territories and Britain's communications with India via the Suez Canal
Suez Canal
The Suez Canal , also known by the nickname "The Highway to India", is an artificial sea-level waterway in Egypt, connecting the Mediterranean Sea and the Red Sea. Opened in November 1869 after 10 years of construction work, it allows water transportation between Europe and Asia without navigation...

. The British and French opened overseas fronts with the Gallipoli (1915) and Mesopotamian campaign
Mesopotamian Campaign
The Mesopotamian campaign was a campaign in the Middle Eastern theatre of World War I fought between the Allies represented by the British Empire, mostly troops from the Indian Empire, and the Central Powers, mostly of the Ottoman Empire.- Background :...

s. In Gallipoli, the Ottoman Empire successfully repelled the British, French, and Australian and New Zealand Army Corps
Australian and New Zealand Army Corps
The Australian and New Zealand Army Corps was a First World War army corps of the Mediterranean Expeditionary Force that was formed in Egypt in 1915 and operated during the Battle of Gallipoli. General William Birdwood commanded the corps, which comprised troops from the First Australian Imperial...

 (ANZACs). In Mesopotamia, by contrast, after the disastrous Siege of Kut
Siege of Kut
The siege of Kut Al Amara , was the besieging of 8,000 strong British-Indian garrison in the town of Kut, 100 miles south of Baghdad, by the Ottoman Army. Its known also as 1st Battle of Kut. In 1915, its population was around 6,500...

 (1915–16), British Imperial forces reorganised and captured Baghdad
Baghdad
Baghdad is the capital of Iraq, as well as the coterminous Baghdad Governorate. The population of Baghdad in 2011 is approximately 7,216,040...

 in March 1917.

Further to the west, the Suez Canal
Suez Canal
The Suez Canal , also known by the nickname "The Highway to India", is an artificial sea-level waterway in Egypt, connecting the Mediterranean Sea and the Red Sea. Opened in November 1869 after 10 years of construction work, it allows water transportation between Europe and Asia without navigation...

 was successfully defended from Ottoman attacks in 1915 and 1916; in August a joint German
German Empire
The German Empire refers to Germany during the "Second Reich" period from the unification of Germany and proclamation of Wilhelm I as German Emperor on 18 January 1871, to 1918, when it became a federal republic after defeat in World War I and the abdication of the Emperor, Wilhelm II.The German...

 and Ottoman
Ottoman Empire
The Ottoman EmpireIt was usually referred to as the "Ottoman Empire", the "Turkish Empire", the "Ottoman Caliphate" or more commonly "Turkey" by its contemporaries...

 force was defeated at the Battle of Romani
Battle of Romani
The Battle of Romani was fought east of the Suez Canal, near the Egyptian town of Romani and the site of ancient Pelusium on the Sinai Peninsula during the First World War...

. Following this victory, a British Empire
British Empire
The British Empire comprised the dominions, colonies, protectorates, mandates and other territories ruled or administered by the United Kingdom. It originated with the overseas colonies and trading posts established by England in the late 16th and early 17th centuries. At its height, it was the...

 force advanced across the Sinai Peninsula
Sinai Peninsula
The Sinai Peninsula or Sinai is a triangular peninsula in Egypt about in area. It is situated between the Mediterranean Sea to the north, and the Red Sea to the south, and is the only part of Egyptian territory located in Asia as opposed to Africa, effectively serving as a land bridge between two...

, pushing Ottoman forces back in the Battle of Magdhaba
Battle of Magdhaba
The Battle of Magdhaba took place on 23 December 1916 south and east of Bir Lahfan in the Sinai desert, some inland from the Mediterranean coast and the town of El Arish...

 in December and the Battle of Rafa
Battle of Rafa
The Battle of Rafa took place on 9 January 1917 at el Magruntein to the south of Rafa, close to the frontier between the Sultanate of Egypt's Sinai Peninsula and the Ottoman Empire, and in the area to the north and east of Sheikh Zowaiid...

 on the border between the Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...

ian Sinai and Ottoman Palestine
Palestine
Palestine is a conventional name, among others, used to describe the geographic region between the Mediterranean Sea and the Jordan River, and various adjoining lands....

 in January 1917. In March and April at the First
First Battle of Gaza
The First Battle of Gaza was fought in and around the town of Gaza on the Mediterranean coast in the southern region of Ottoman Palestine on 26 March 1917, during World War I...

 and Second Battles of Gaza
Second Battle of Gaza
The Second Battle of Gaza, fought in southern Palestine during the First World War, was another attempt mounted by British Empire forces to break Ottoman defences along the Gaza-Beersheba line...

, German and Ottoman forces stopped the advance, but at the end of October the Sinai and Palestine Campaign
Sinai and Palestine Campaign
The Sinai and Palestine Campaigns took place in the Middle Eastern Theatre of World War I. A series of battles were fought between British Empire, German Empire and Ottoman Empire forces from 26 January 1915 to 31 October 1918, when the Armistice of Mudros was signed between the Ottoman Empire and...

 resumed, when Allenby
Edmund Allenby, 1st Viscount Allenby
Field Marshal Edmund Henry Hynman Allenby, 1st Viscount Allenby GCB, GCMG, GCVO was a British soldier and administrator most famous for his role during the First World War, in which he led the Egyptian Expeditionary Force in the conquest of Palestine and Syria in 1917 and 1918.Allenby, nicknamed...

's Egyptian Expeditionary Force
Egyptian Expeditionary Force
The Egyptian Expeditionary Force was formed in March 1916 to command the British and British Empire military forces in Egypt during World War I. Originally known as the 'Force in Egypt' it had been commanded by General Maxwell who was recalled to England...

 won the Battle of Beersheba. Two Ottoman armies were defeated a few weeks later at the Battle of Mughar Ridge
Battle of Mughar Ridge
The Battle of El Mughar Ridge , took place on 13 November 1917 during the Sinai and Palestine Campaign of the First World War...

, and early in December Jerusalem was captured following another Ottoman defeat at the Battle of Jerusalem (1917)
Battle of Jerusalem (1917)
The Battle of Jerusalem developed from 17 November with fighting continuing until 30 December 1917 during the Sinai and Palestine Campaign of World War I...

. About this time Friedrich Freiherr Kress von Kressenstein was relieved of his duties as the Eighth Army's commander, replaced by Djevad Pasha
Cevat Çobanli
Cevat Çobanlı was a military commander of the Ottoman Army, War Minister of the Ottoman Empire and a general of Turkish Army.-Family and schools:...

, and a few months later the commander of the Ottoman Army in Palestine, Erich von Falkenhayn
Erich von Falkenhayn
Erich von Falkenhayn was a German soldier and Chief of the General Staff during World War I. He became a military writer after World War I.-Early life:...

, was replaced by Otto Liman von Sanders
Otto Liman von Sanders
Generalleutnant Otto Liman von Sanders was a German general who served as adviser and military commander for the Ottoman Empire during World War I.-Biography:...

.

The Egyptian Expeditionary Force, under Field Marshal Edmund Allenby, broke the Ottoman forces at the Battle of Megiddo
Battle of Megiddo (1918)
The Battle of Megiddo took place between 19 September and 1 October 1918, in what was then the northern part of Ottoman Palestine and parts of present-day Syria and Jordan...

 in September 1918. In six weeks, during virtually continuous operations, battles were successfully fought by British infantry and Australian, New Zealand, and British Light Horse
Light Horse
Australian Light Horse were mounted troops with characteristics of both cavalry and mounted infantry. They served during the Second Boer War and World War I...

, Mounted Rifle and Yeomanry
Yeomanry
Yeomanry is a designation used by a number of units or sub-units of the British Territorial Army, descended from volunteer cavalry regiments. Today, Yeomanry units may serve in a variety of different military roles.-History:...

 mounted brigades. They campaigned across the Jordan River to Amman
Amman
Amman is the capital of Jordan. It is the country's political, cultural and commercial centre and one of the oldest continuously inhabited cities in the world. The Greater Amman area has a population of 2,842,629 as of 2010. The population of Amman is expected to jump from 2.8 million to almost...

 in the east and northwards to capture Nablus
Nablus
Nablus is a Palestinian city in the northern West Bank, approximately north of Jerusalem, with a population of 126,132. Located in a strategic position between Mount Ebal and Mount Gerizim, it is the capital of the Nablus Governorate and a Palestinian commercial and cultural center.Founded by the...

 and Tulkarm
Tulkarm
Tulkarem or Tulkarm is a Palestinian city in the northern Samarian mountain range in the Tulkarm Governorate in the extreme northwestern West Bank adjacent to the Netanya and Haifa districts to the west, the Nablus and Jenin Districts to the east...

 in the Judean Hills, and followed the Mediterranean coast into the Jezreel Valley
Jezreel Valley
-Etymology:The Jezreel Valley takes its name from the ancient city of Jezreel which was located on a low hill overlooking the southern edge of the valley, though some scholars think that the name of the city originates from the name of the clan which founded it, and whose existence is mentioned in...

 (Esdraelon Plain), where Jenin
Jenin
Jenin is the largest town in the Northern West Bank, and the third largest city overall. It serves as the administrative center of the Jenin Governorate and is a major agricultural center for the surrounding towns. In 2007, the city had a population of 120,004 not including the adjacent refugee...

 and Nazareth
Nazareth
Nazareth is the largest city in the North District of Israel. Known as "the Arab capital of Israel," the population is made up predominantly of Palestinian Arab citizens of Israel...

 were captured, along with Daraa on the Hejaz railway, Semakh and Tiberias on the Sea of Gallilee, and finally Damascus
Damascus
Damascus , commonly known in Syria as Al Sham , and as the City of Jasmine , is the capital and the second largest city of Syria after Aleppo, both are part of the country's 14 governorates. In addition to being one of the oldest continuously inhabited cities in the world, Damascus is a major...

 and Aleppo
Aleppo
Aleppo is the largest city in Syria and the capital of Aleppo Governorate, the most populous Syrian governorate. With an official population of 2,301,570 , expanding to over 2.5 million in the metropolitan area, it is also one of the largest cities in the Levant...

. The Armistice of Mudros
Armistice of Mudros
The Armistice of Moudros , concluded on 30 October 1918, ended the hostilities in the Middle Eastern theatre between the Ottoman Empire and the Allies of World War I...

 was signed on 30 October, when two and a half Ottoman armies had been defeated and captured.

Russian armies generally had the best of it in the Caucasus. Enver Pasha, supreme commander of the Ottoman armed forces, was ambitious and dreamed of re-conquering central Asia and areas that had been lost to Russia previously. He was, however, a poor commander. He launched an offensive against the Russians in the Caucasus in December 1914 with 100,000 troops; insisting on a frontal attack against mountainous Russian positions in winter, he lost 86% of his force at the Battle of Sarikamish.

General Yudenich, the Russian commander from 1915 to 1916, drove the Turks out of most of the southern Caucasus with a string of victories. In 1917, Russian Grand Duke Nicholas assumed command of the Caucasus front. Nicholas planned a railway from Russian Georgia
Georgia (country)
Georgia is a sovereign state in the Caucasus region of Eurasia. Located at the crossroads of Western Asia and Eastern Europe, it is bounded to the west by the Black Sea, to the north by Russia, to the southwest by Turkey, to the south by Armenia, and to the southeast by Azerbaijan. The capital of...

 to the conquered territories, so that fresh supplies could be brought up for a new offensive in 1917. However, in March 1917 (February in the pre-revolutionary Russian calendar), the Czar was overthrown in the February Revolution
February Revolution
The February Revolution of 1917 was the first of two revolutions in Russia in 1917. Centered around the then capital Petrograd in March . Its immediate result was the abdication of Tsar Nicholas II, the end of the Romanov dynasty, and the end of the Russian Empire...

 and the Russian Caucasus Army began to fall apart.
Instigated by the Arab bureau of the British Foreign and Commonwealth Office
Foreign and Commonwealth Office
The Foreign and Commonwealth Office, commonly called the Foreign Office or the FCO is a British government department responsible for promoting the interests of the United Kingdom overseas, created in 1968 by merging the Foreign Office and the Commonwealth Office.The head of the FCO is the...

, the Arab Revolt
Arab Revolt
The Arab Revolt was initiated by the Sherif Hussein bin Ali with the aim of securing independence from the ruling Ottoman Turks and creating a single unified Arab state spanning from Aleppo in Syria to Aden in Yemen.- Background :...

 started with the help of Britain in June 1916 at the Battle of Mecca
Battle of Mecca 1916
The Battle of Mecca occurred in the Muslim holy city of Mecca in June and July 1916. On June 10, the Sharif of Mecca, Hussein bin Ali, the leader of the Binu Hashim clan started a revolt against the Ottoman Caliphate from this city. The Battle of Mecca was part of the Arab Revolt of World War...

, led by Sherif Hussein of Mecca
Mecca
Mecca is a city in the Hijaz and the capital of Makkah province in Saudi Arabia. The city is located inland from Jeddah in a narrow valley at a height of above sea level...

, and ended with the Ottoman surrender of Damascus. Fakhri Pasha
Fakhri Pasha
Fakhri Pasha or Fahreddin Pasha or Umar Fakhr ud-Din Pasha was the commander of Ottoman army and governor of Medina from 1916 to 1919.-Early life:...

, the Ottoman commander of Medina
Medina
Medina , or ; also transliterated as Madinah, or madinat al-nabi "the city of the prophet") is a city in the Hejaz region of western Saudi Arabia, and serves as the capital of the Al Madinah Province. It is the second holiest city in Islam, and the burial place of the Islamic Prophet Muhammad, and...

, resisted for more than two and half years during the Siege of Medina
Siege of Medina
Medina, an Islamic holy city in Arabia, underwent a long siege during World War I. Medina was at the time part of the Ottoman Empire. In the war, the Ottoman Empire sided with the Central Powers...

.

Along the border of Italian Libya and British Egypt, the Senussi
Senussi
The Senussi or Sanussi refers to a Muslim political-religious order in Libya and the Sudan region founded in Mecca in 1837 by the Grand Senussi, Sayyid Muhammad ibn Ali as-Senussi. Senussi was concerned with both the decline of Islamic thought and spirituality and the weakening of Muslim political...

 tribe, incited and armed by the Turks, waged a small-scale guerrilla war against Allied troops. The British were forced to dispatch 12,000 troops to oppose them in the Senussi Campaign. Their rebellion was finally crushed in mid-1916.

Italian participation

Italy had been allied with the German and Austro-Hungarian Empires since 1882 as part of the Triple Alliance
Triple Alliance (1882)
The Triple Alliance was the military alliance between Germany, Austria–Hungary, and Italy, , that lasted from 1882 until the start of World War I in 1914...

. However, the nation had its own designs on Austrian territory in Trentino, Istria
Istria
Istria , formerly Histria , is the largest peninsula in the Adriatic Sea. The peninsula is located at the head of the Adriatic between the Gulf of Trieste and the Bay of Kvarner...

, and Dalmatia
Dalmatia
Dalmatia is a historical region on the eastern coast of the Adriatic Sea. It stretches from the island of Rab in the northwest to the Bay of Kotor in the southeast. The hinterland, the Dalmatian Zagora, ranges from fifty kilometers in width in the north to just a few kilometers in the south....

. Rome had a secret 1902 pact with France, effectively nullifying its alliance. At the start of hostilities, Italy refused to commit troops, arguing that the Triple Alliance was defensive and that Austria–Hungary was an aggressor. The Austro-Hungarian government began negotiations to secure Italian neutrality, offering the French colony of Tunisia
Tunisia
Tunisia , officially the Tunisian RepublicThe long name of Tunisia in other languages used in the country is: , is the northernmost country in Africa. It is a Maghreb country and is bordered by Algeria to the west, Libya to the southeast, and the Mediterranean Sea to the north and east. Its area...

 in return. The Allies made a counter-offer in which Italy would receive the Southern Tyrol, Julian March
Julian March
The Julian March is a former political region of southeastern Europe on what are now the borders between Croatia, Slovenia, and Italy...

 and territory on the Dalmatia
Dalmatia
Dalmatia is a historical region on the eastern coast of the Adriatic Sea. It stretches from the island of Rab in the northwest to the Bay of Kotor in the southeast. The hinterland, the Dalmatian Zagora, ranges from fifty kilometers in width in the north to just a few kilometers in the south....

n coast after the defeat of Austria-Hungary. This was formalised by the Treaty of London. Further encouraged by the Allied invasion of Turkey in April 1915, Italy joined the Triple Entente and declared war on Austria-Hungary on 23 May. Fifteen months later Italy declared war on Germany.

Militarily, the Italians had numerical superiority. This advantage, however, was lost, not only because of the difficult terrain in which fighting took place, but also because of the strategies and tactics employed. Field Marshal
Field Marshal
Field Marshal is a military rank. Traditionally, it is the highest military rank in an army.-Etymology:The origin of the rank of field marshal dates to the early Middle Ages, originally meaning the keeper of the king's horses , from the time of the early Frankish kings.-Usage and hierarchical...

 Luigi Cadorna
Luigi Cadorna
Luigi Cadorna GCB was an ItalianField Marshal, most famous for being thechief of staff of the Italian army during the first part of World War I.-Biography:...

, a staunch proponent of the frontal assault, had dreams of breaking into the Slovenian plateau, taking Ljubljana
Ljubljana
Ljubljana is the capital of Slovenia and its largest city. It is the centre of the City Municipality of Ljubljana. It is located in the centre of the country in the Ljubljana Basin, and is a mid-sized city of some 270,000 inhabitants...

 and threatening Vienna
Vienna
Vienna is the capital and largest city of the Republic of Austria and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.723 million , and is by far the largest city in Austria, as well as its cultural, economic, and political centre...

. It was a Napoleonic
Napoleonic Wars
The Napoleonic Wars were a series of wars declared against Napoleon's French Empire by opposing coalitions that ran from 1803 to 1815. As a continuation of the wars sparked by the French Revolution of 1789, they revolutionised European armies and played out on an unprecedented scale, mainly due to...

 plan, which had no realistic chance of success in an age of barbed wire, machine guns, and indirect artillery fire, combined with hilly and mountainous terrain.

On the Trentino front, the Austro-Hungarians took advantage of the mountainous terrain, which favoured the defender. After an initial strategic retreat, the front remained largely unchanged, while Austrian Kaiserschützen
Kaiserschützen
The Kaiserschützen were three regiments of Austro-Hungarian mountain infantry during the K.U.K. Monarchy.-History:...

 and Standschützen engaged Italian Alpini
Alpini
The Alpini, , are the elite mountain warfare soldiers of the Italian Army. They are currently organized in two operational brigades, which are subordinated to the Alpini Corps Command. The singular is Alpino ....

 in bitter hand-to-hand combat throughout the summer. The Austro-Hungarians counterattacked in the Altopiano of Asiago
Asiago
Asiago is the name of both a minor township and the surrounding plateau region in the Province of Vicenza in the Veneto region of Northeastern Italy...

, towards Verona and Padua, in the spring of 1916 (Strafexpedition
Battle of Asiago
The Battle of Asiago ' or the Trentino Offensive , nicknamed Strafexpedition by the Austrians, was a counteroffensive launched by the Austro-Hungarians on the Italian Front on 15 May 1916, during World War I...

), but made little progress.

Beginning in 1915, the Italians under Cadorna mounted eleven offensives on the Isonzo front
Soca
The Soča or Isonzo is a 140 km long river that flows through western Slovenia and northeastern Italy. An Alpine river in character, its source lies in the Trenta Valley in the Julian Alps in Slovenia, at an elevation of around 1,100 metres...

 along the Isonzo River
Soca
The Soča or Isonzo is a 140 km long river that flows through western Slovenia and northeastern Italy. An Alpine river in character, its source lies in the Trenta Valley in the Julian Alps in Slovenia, at an elevation of around 1,100 metres...

, northeast of Trieste
Trieste
Trieste is a city and seaport in northeastern Italy. It is situated towards the end of a narrow strip of land lying between the Adriatic Sea and Italy's border with Slovenia, which lies almost immediately south and east of the city...

. All eleven offensives were repelled by the Austro-Hungarians, who held the higher ground. In the summer of 1916, the Italians captured the town of Gorizia
Gorizia
Gorizia is a town and comune in northeastern Italy, in the autonomous region of Friuli Venezia Giulia. It is located at the foot of the Julian Alps, bordering Slovenia. It is the capital of the Province of Gorizia, and it is a local center of tourism, industry, and commerce. Since 1947, a twin...

. After this minor victory, the front remained static for over a year, despite several Italian offensives. In the autumn of 1917, thanks to the improving situation on the Eastern front, the Austro-Hungarian troops received large numbers of reinforcements, including German Stormtrooper
Stormtrooper
Stormtroopers were specialist soldiers of the German Army in World War I. In the last years of the war, Stoßtruppen were trained to fight with "infiltration tactics", part of the Germans' new method of attack on enemy trenches...

s and the elite Alpenkorps
Alpenkorps (German Empire)
The Alpenkorps was a provisional mountain unit of division size formed by the Imperial German Army during World War I. It was considered by the Allies to be one of the best units of the German Army.-Formation:...

. The Central Powers launched a crushing offensive on 26 October 1917, spearheaded by the Germans. They achieved a victory at Caporetto
Battle of Caporetto
The Battle of Caporetto , took place from 24 October to 19 November 1917, near the town of Kobarid , on the Austro-Italian front of World War I...

. The Italian Army was routed and retreated more than 100 kilometres (62.1 mi) to reorganise, stabilising the front at the Piave River
Battle of the Piave River
The Battle of the Piave River , known in Italy as Battaglia del Solstizio , Battaglia di Mezzo Giugno , or Seconda Battaglia del Piave , was a decisive victory for the Italian Army during World War...

. Since in the Battle of Caporetto the Italian Army had heavy losses, the Italian Government called to arms the so-called 99 Boys (Ragazzi del '99): that is, all males who were 18 years old. In 1918, the Austro-Hungarians failed to break through, in a series of battles on the Piave River
Battle of the Piave River
The Battle of the Piave River , known in Italy as Battaglia del Solstizio , Battaglia di Mezzo Giugno , or Seconda Battaglia del Piave , was a decisive victory for the Italian Army during World War...

, and were finally decisively defeated in the Battle of Vittorio Veneto
Battle of Vittorio Veneto
The Battle of Vittorio Veneto was fought between 24 October and 3 November 1918, near Vittorio Veneto, during the Italian Campaign of World War I...

 in October of that year. Austria-Hungary surrendered in early November 1918.

Romanian participation

Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

 had been allied with the Central Powers since 1882. When the war began, however, it declared its neutrality, arguing that because Austria-Hungary had itself declared war on Serbia, Romania was under no obligation to join the war. When the Entente Powers promised Romania large territories of eastern Hungary (Transylvania
Transylvania
Transylvania is a historical region in the central part of Romania. Bounded on the east and south by the Carpathian mountain range, historical Transylvania extended in the west to the Apuseni Mountains; however, the term sometimes encompasses not only Transylvania proper, but also the historical...

 and Banat
Banat
The Banat is a geographical and historical region in Central Europe currently divided between three countries: the eastern part lies in western Romania , the western part in northeastern Serbia , and a small...

) that had a large Romanian population in exchange for Romania’s declaring war on the Central Powers, the Romanian government renounced its neutrality, and on 27 August 1916 the Romanian Army launched an attack
Battle of Transylvania
The Battle of Transylvania was the first major operation of the Romanian Campaign during World War I, beginning on 15 August 1916. It started as an attempt by the Romanian Army to seize the disputed province of Transylvania and potentially knock Austria-Hungary out of the war...

 against Austria-Hungary, with limited Russian support. The Romanian offensive was initially successful, pushing back the Austro-Hungarian troops in Transylvania, but a counterattack by the forces of the Central Powers
Central Powers
The Central Powers were one of the two warring factions in World War I , composed of the German Empire, the Austro-Hungarian Empire, the Ottoman Empire, and the Kingdom of Bulgaria...

 drove back the Russo-Romanian forces. As a result of the Battle of Bucharest
Battle of Bucharest
The Battle of Bucharest, also known as the Argeş-Neajlov Defensive Operation in Romania, was an important battle of the Romanian Campaign in World War I, in which the Central Powers occupied the Romanian capital and forced the Romanian Government, as well as the remnants of the Romanian Army to...

 the Central Powers occupied Bucharest on 6 December 1916. Fighting in Moldova continued in 1917, resulting in a costly stalemate for the Central Powers. As Russia withdrew from the war in late 1917 as a result of the October Revolution
October Revolution
The October Revolution , also known as the Great October Socialist Revolution , Red October, the October Uprising or the Bolshevik Revolution, was a political revolution and a part of the Russian Revolution of 1917...

, and Romania was forced to sign an armistice with the Central Powers on 9 December 1917.

In January 1918, Romanian forces established control over Bessarabia
Bessarabia
Bessarabia is a historical term for the geographic region in Eastern Europe bounded by the Dniester River on the east and the Prut River on the west....

 as the Russian Army abandoned the province. Although a treaty was signed by the Romanian and the Bolshevik
Bolshevik
The Bolsheviks, originally also Bolshevists , derived from bol'shinstvo, "majority") were a faction of the Marxist Russian Social Democratic Labour Party which split apart from the Menshevik faction at the Second Party Congress in 1903....

 Russian government following talks from 5–9 March 1918 on the withdrawal of Romanian forces from Bessarabia within two months, on 27 March 1918 Romania attached Bessarabia to its territory, formally based on a resolution passed by the local assembly of the territory on the unification with Romania.

Romania officially made peace with the Central Powers by signing the Treaty of Bucharest on 7 May 1918. Under that treaty, Romania was obliged to end war with the Central Powers and make small territorial concessions to Austria-Hungary, ceding control of some passes in the Carpathian Mountains
Carpathian Mountains
The Carpathian Mountains or Carpathians are a range of mountains forming an arc roughly long across Central and Eastern Europe, making them the second-longest mountain range in Europe...

, and grant oil concessions to Germany. In exchange, the Central Powers recognised the sovereignty of Romania over Bessarabia
Bessarabia
Bessarabia is a historical term for the geographic region in Eastern Europe bounded by the Dniester River on the east and the Prut River on the west....

. The treaty was renounced in October 1918 by the Alexandru Marghiloman
Alexandru Marghiloman
Alexandru Marghiloman was a Romanian conservative statesman who served for a short time in 1918 as Prime Minister of Romania, and had a decisive role during World War I.-Early career:...

 government, and Romania nominally re-entered the war on 10 November 1918. The next day, the Treaty of Bucharest was nullified by the terms of the Armistice of Compiègne
Compiègne
Compiègne is a city in northern France. It is designated municipally as a commune within the département of Oise.The city is located along the Oise River...

. Total Romanian deaths from 1914 to 1918, military and civilian, within contemporary borders, were estimated at 748,000.

The role of India

The war began with an unprecedented outpouring of loyalty and good will towards the United Kingdom from within the mainstream political leadership, contrary to initial British fears of an Indian revolt. The Indian Army
British Indian Army
The British Indian Army, officially simply the Indian Army, was the principal army of the British Raj in India before the partition of India in 1947...

 in fact outnumbered the British Army at the beginning of the war. India under British rule contributed greatly to the British war effort by providing men and resources. This was done by the Indian Congress in hope of achieving self-government, as India was very much under the control of the British. The United Kingdom disappointed the Indians by not providing self-governance, leading to the Gandhian Era in Indian history. About 1.3 million Indian soldiers and labourers served in Europe, Africa, and the Middle East, while both the Indian government and the princes sent large supplies of food, money, and ammunition. In all, 140,000 men served on the Western Front and nearly 700,000 in the Middle East. Casualties of Indian soldiers totalled 47,746 killed and 65,126 wounded during World War I.

Initial actions

While the Western Front had reached stalemate, the war continued in East Europe. Initial Russian plans called for simultaneous invasions of Austrian Galicia
Kingdom of Galicia and Lodomeria
The Kingdom of Galicia and Lodomeria was a crownland of the Habsburg Monarchy, the Austrian Empire, and Austria–Hungary from 1772 to 1918 .This historical region in eastern Central Europe is currently divided between Poland and Ukraine...

 and German East Prussia. Although Russia's initial advance into Galicia was largely successful, it was driven back from East Prussia by Hindenburg
Paul von Hindenburg
Paul Ludwig Hans Anton von Beneckendorff und von Hindenburg , known universally as Paul von Hindenburg was a Prussian-German field marshal, statesman, and politician, and served as the second President of Germany from 1925 to 1934....

 and Ludendorff
Erich Ludendorff
Erich Friedrich Wilhelm Ludendorff was a German general, victor of Liège and of the Battle of Tannenberg...

 at Tannenberg
Battle of Tannenberg (1914)
The Battle of Tannenberg was an engagement between the Russian Empire and the German Empire in the first days of World War I. It was fought by the Russian First and Second Armies against the German Eighth Army between 23 August and 30 August 1914. The battle resulted in the almost complete...

 and the Masurian Lakes in August and September 1914. Russia's less developed industrial base and ineffective military leadership was instrumental in the events that unfolded. By the spring of 1915, the Russians had retreated into Galicia, and in May the Central Powers achieved a remarkable breakthrough on Poland's southern frontiers. On 5 August they captured Warsaw
Warsaw
Warsaw is the capital and largest city of Poland. It is located on the Vistula River, roughly from the Baltic Sea and from the Carpathian Mountains. Its population in 2010 was estimated at 1,716,855 residents with a greater metropolitan area of 2,631,902 residents, making Warsaw the 10th most...

 and forced the Russians to withdraw from Poland.

Russian Revolution

Despite the success of the June 1916 Brusilov Offensive
Brusilov Offensive
The Brusilov Offensive , also known as the June Advance, was the Russian Empire's greatest feat of arms during World War I, and among the most lethal battles in world history. Prof. Graydon A. Tunstall of the University of South Florida called the Brusilov Offensive of 1916 the worst crisis of...

 in eastern Galicia
Kingdom of Galicia and Lodomeria
The Kingdom of Galicia and Lodomeria was a crownland of the Habsburg Monarchy, the Austrian Empire, and Austria–Hungary from 1772 to 1918 .This historical region in eastern Central Europe is currently divided between Poland and Ukraine...

, dissatisfaction with the Russian government's conduct of the war grew. The offensive's success was undermined by the reluctance of other generals to commit their forces to support the victory. Allied and Russian forces were revived only temporarily by Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

's entry into the war on 27 August. German forces came to the aid of embattled Austro-Hungarian units in Transylvania
Transylvania
Transylvania is a historical region in the central part of Romania. Bounded on the east and south by the Carpathian mountain range, historical Transylvania extended in the west to the Apuseni Mountains; however, the term sometimes encompasses not only Transylvania proper, but also the historical...

, and Bucharest
Bucharest
Bucharest is the capital municipality, cultural, industrial, and financial centre of Romania. It is the largest city in Romania, located in the southeast of the country, at , and lies on the banks of the Dâmbovița River....

 fell to the Central Powers on 6 December. Meanwhile, unrest grew in Russia, as the Tsar
Nicholas II of Russia
Nicholas II was the last Emperor of Russia, Grand Prince of Finland, and titular King of Poland. His official short title was Nicholas II, Emperor and Autocrat of All the Russias and he is known as Saint Nicholas the Passion-Bearer by the Russian Orthodox Church.Nicholas II ruled from 1894 until...

 remained at the front. Empress Alexandra's increasingly incompetent rule drew protests and resulted in the murder of her favourite, Rasputin
Grigori Rasputin
Grigori Yefimovich Rasputin was a Russian Orthodox Christian and mystic who is perceived as having influenced the latter days of the Russian Emperor Nicholas II, his wife Alexandra, and their only son Alexei...

, at the end of 1916.

In March 1917, demonstrations in Petrograd
Saint Petersburg
Saint Petersburg is a city and a federal subject of Russia located on the Neva River at the head of the Gulf of Finland on the Baltic Sea...

 culminated in the abdication of Tsar Nicholas II
Nicholas II of Russia
Nicholas II was the last Emperor of Russia, Grand Prince of Finland, and titular King of Poland. His official short title was Nicholas II, Emperor and Autocrat of All the Russias and he is known as Saint Nicholas the Passion-Bearer by the Russian Orthodox Church.Nicholas II ruled from 1894 until...

 and the appointment of a weak Provisional Government
Russian Provisional Government
The Russian Provisional Government was the short-lived administrative body which sought to govern Russia immediately following the abdication of Tsar Nicholas II . On September 14, the State Duma of the Russian Empire was officially dissolved by the newly created Directorate, and the country was...

 which shared power with the Petrograd Soviet
Petrograd Soviet
The Petrograd Soviet of Workers' and Soldiers' Deputies , usually called the Petrograd Soviet , was the soviet in Petrograd , Russia, established in March 1917 after the February Revolution as the representative body of the city's workers.The Petrograd Soviet became important during the Russian...

 socialists. This arrangement led to confusion and chaos both at the front and at home. The army became increasingly ineffective.
The war and the government became increasingly unpopular. Discontent led to a rise in popularity of the Bolshevik
Bolshevik
The Bolsheviks, originally also Bolshevists , derived from bol'shinstvo, "majority") were a faction of the Marxist Russian Social Democratic Labour Party which split apart from the Menshevik faction at the Second Party Congress in 1903....

 Party, led by Vladimir Lenin
Vladimir Lenin
Vladimir Ilyich Lenin was a Russian Marxist revolutionary and communist politician who led the October Revolution of 1917. As leader of the Bolsheviks, he headed the Soviet state during its initial years , as it fought to establish control of Russia in the Russian Civil War and worked to create a...

. He promised to pull Russia out of the war and was able to gain power. The triumph of the Bolsheviks
October Revolution
The October Revolution , also known as the Great October Socialist Revolution , Red October, the October Uprising or the Bolshevik Revolution, was a political revolution and a part of the Russian Revolution of 1917...

 in November was followed in December by an armistice and negotiations with Germany. At first the Bolsheviks refused the German terms, but when Germany resumed the war and marched across Ukraine
Ukraine
Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...

 with impunity, the new government acceded to the Treaty of Brest-Litovsk
Treaty of Brest-Litovsk
The Treaty of Brest-Litovsk was a peace treaty signed on March 3, 1918, mediated by South African Andrik Fuller, at Brest-Litovsk between Russia and the Central Powers, headed by Germany, marking Russia's exit from World War I.While the treaty was practically obsolete before the end of the year,...

 on 3 March 1918. It took Russia out of the war and ceded vast territories, including Finland, the Baltic provinces
Baltic states
The term Baltic states refers to the Baltic territories which gained independence from the Russian Empire in the wake of World War I: primarily the contiguous trio of Estonia, Latvia, Lithuania ; Finland also fell within the scope of the term after initially gaining independence in the 1920s.The...

, parts of Poland and Ukraine
Ukraine
Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...

 to the Central Powers. The manpower required for German occupation of former Russian territory may have contributed to the failure of the Spring Offensive, however, and secured relatively little food or other materiel
Materiel
Materiel is a term used in English to refer to the equipment and supplies in military and commercial supply chain management....

.

With the adoption of the Treaty of Brest-Litovsk, the Entente no longer existed. The Allied powers led a small-scale invasion
Allied Intervention in the Russian Civil War
The Allied intervention was a multi-national military expedition launched in 1918 during World War I which continued into the Russian Civil War. Its operations included forces from 14 nations and were conducted over a vast territory...

 of Russia, partly to stop Germany from exploiting Russian resources and, to a lesser extent, to support the "Whites" (as opposed to the "Reds") in the Russian Civil War
Russian Civil War
The Russian Civil War was a multi-party war that occurred within the former Russian Empire after the Russian provisional government collapsed to the Soviets, under the domination of the Bolshevik party. Soviet forces first assumed power in Petrograd The Russian Civil War (1917–1923) was a...

. Allied troops landed in Archangel
Arkhangelsk
Arkhangelsk , formerly known as Archangel in English, is a city and the administrative center of Arkhangelsk Oblast, Russia. It lies on both banks of the Northern Dvina River near its exit into the White Sea in the north of European Russia. The city spreads for over along the banks of the river...

 and in Vladivostok
Vladivostok
The city is located in the southern extremity of Muravyov-Amursky Peninsula, which is about 30 km long and approximately 12 km wide.The highest point is Mount Kholodilnik, the height of which is 257 m...

.

Central Powers proposal for starting peace negotiations

In December 1916, after ten brutal months of the Battle of Verdun
Battle of Verdun
The Battle of Verdun was one of the major battles during the First World War on the Western Front. It was fought between the German and French armies, from 21 February – 18 December 1916, on hilly terrain north of the city of Verdun-sur-Meuse in north-eastern France...

 and a successful offensive against Romania, the Germans attempted to negotiate a peace with the Allies. Soon after, U.S. President Woodrow Wilson attempted to intervene as a peacemaker, asking in a note for both sides to state their demands. Lloyd George's War Cabinet considered the German offer to be a ploy to create divisions amongst the Allies. After initial outrage and much deliberation, they took Wilson's note as a separate effort, signalling that the U.S. was on the verge of entering the war against Germany following the "submarine outrages". While the Allies debated a response to Wilson's offer, the Germans chose to rebuff it in favour of "a direct exchange of views". Learning of the German response, the Allied governments were free to make clear demands in their response of 14 January. They sought restoration of damages, the evacuation of occupied territories, reparations for France, Russia and Romania, and a recognition of the principle of nationalities. This included the liberation of Italians, Slavs, Romanians, Czecho-Slovaks, and the creation of a "free and united Poland". On the question of security, the Allies sought guarantees that would prevent or limit future wars, complete with sanctions, as a condition of any peace settlement. The negotiations failed and the Entente powers rejected the German offer, because Germany did not state any specific proposals. To Wilson, the Entente powers stated that they would not start peace negotiations until the Central powers evacuated all occupied Allied territories and provided indemnities for all damage which had been done.

1917–1918

Developments in 1917

Events of 1917 proved decisive in ending the war, although their effects were not fully felt until 1918.

The British naval blockade began to have a serious impact on Germany. In response, in February 1917, the German General Staff
German General Staff
The German General Staff was an institution whose rise and development gave the German armed forces a decided advantage over its adversaries. The Staff amounted to its best "weapon" for nearly a century and a half....

 convinced Chancellor
Chancellor
Chancellor is the title of various official positions in the governments of many nations. The original chancellors were the Cancellarii of Roman courts of justice—ushers who sat at the cancelli or lattice work screens of a basilica or law court, which separated the judge and counsel from the...

 Theobald von Bethmann-Hollweg
Theobald von Bethmann-Hollweg
Theobald von Bethmann Hollweg was a German politician and statesman who served as Chancellor of the German Empire from 1909 to 1917.-Origins:...

 to declare unrestricted submarine warfare, with the goal of starving Britain out of the war. German planners estimated that unrestricted submarine warfare would cost Britain a monthly shipping loss of 600,000 tons. While it was realised that the policy was also likely to bring the United States into the conflict, British shipping losses would be so high that it would be forced to sue for peace after 5 to 6 months, before American intervention could make an impact. In reality, tonnage sunk rose above 500,000 tons per month from February to July. It peaked at 860,000 tons in April. After July, the newly re-introduced convoy
Convoy
A convoy is a group of vehicles, typically motor vehicles or ships, traveling together for mutual support and protection. Often, a convoy is organized with armed defensive support, though it may also be used in a non-military sense, for example when driving through remote areas.-Age of Sail:Naval...

 system became extremely effective in reducing the U-boat
U-boat
U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...

 threat. Britain was safe from starvation while German industrial output fell, and the United States troops joined the war in large numbers far earlier than Germany had anticipated.

On 3 May 1917, during the Nivelle Offensive
Nivelle offensive
The Nivelle Offensive was a 1917 French attack on the Western Front in the First World War. Promised as the assault that would end the war within 48 hours, with casualties expected of around 10,000 men, it failed on both counts. It was a three-stage plan:...

, the weary French 2nd Colonial Division, veterans of the Battle of Verdun, refused their orders, arriving drunk and without their weapons. Their officers lacked the means to punish an entire division, and harsh measures were not immediately implemented. Then, mutinies
French Army Mutinies (1917)
The French Army Mutinies of 1917 took place amongst the French troops on the Western Front in Northern France. They started just after the conclusion of the disastrous Second Battle of the Aisne, the main action in the Nivelle Offensive, and involved, to various degrees, nearly half of the French...

 afflicted an additional 54 French divisions and saw 20,000 men desert. The other Allied forces attacked but sustained tremendous casualties. However, appeals to patriotism and duty, as well as mass arrests and trials, encouraged the soldiers to return to defend their trenches, although the French soldiers refused to participate in further offensive action. Robert Nivelle
Robert Nivelle
Robert Georges Nivelle was a French artillery officer who served in the Boxer Rebellion, and the First World War. In May 1916, he was given command of the French Third Army in the Battle of Verdun, leading counter-offensives that rolled back the German forces in late 1916...

 was removed from command by 15 May, replaced by General Philippe Pétain
Philippe Pétain
Henri Philippe Benoni Omer Joseph Pétain , generally known as Philippe Pétain or Marshal Pétain , was a French general who reached the distinction of Marshal of France, and was later Chief of State of Vichy France , from 1940 to 1944...

, who suspended bloody large-scale attacks.

The victory of Austria–Hungary and Germany at the Battle of Caporetto
Battle of Caporetto
The Battle of Caporetto , took place from 24 October to 19 November 1917, near the town of Kobarid , on the Austro-Italian front of World War I...

 led the Allies at the Rapallo Conference
Rapallo Conference
The Rapallo Conference was convened by the allied powers of World War I, on the fifth of November 1917 in Rapallo, Italy, following their defeat by Germany at the Battle of Caporetto....

 to form the Supreme War Council
Supreme War Council
The Supreme War Council was a central command created by British Prime Minister David Lloyd George to coordinate Allied military strategy during World War I. It was founded in 1917, and was based in Versailles...

 to coordinate planning. Previously, British and French armies had operated under separate commands.

In December, the Central Powers signed an armistice with Russia. This released large numbers of German troops for use in the west. With German reinforcements and new American troops pouring in, the outcome was to be decided on the Western Front. The Central Powers knew that they could not win a protracted war, but they held high hopes for success based on a final quick offensive. Furthermore, the leaders of the Central Powers and the Allies became increasingly fearful of social unrest and revolution in Europe. Thus, both sides urgently sought a decisive victory.
Non-Intervention

At the outbreak of the war the United States pursued a policy of non-intervention, avoiding conflict while trying to broker a peace. When a German U-boat sank the British liner Lusitania
RMS Lusitania
RMS Lusitania was a British ocean liner designed by Leonard Peskett and built by John Brown and Company of Clydebank, Scotland. The ship entered passenger service with the Cunard Line on 26 August 1907 and continued on the line's heavily-traveled passenger service between Liverpool, England and New...

 in 1915, with 128 Americans aboard, U.S. President Woodrow Wilson
Woodrow Wilson
Thomas Woodrow Wilson was the 28th President of the United States, from 1913 to 1921. A leader of the Progressive Movement, he served as President of Princeton University from 1902 to 1910, and then as the Governor of New Jersey from 1911 to 1913...

 claimed that "America is too proud to fight" but demanded an end to attacks on passenger ships. Germany complied. Wilson unsuccessfully tried to mediate a settlement. However, he also repeatedly warned that the U.S.A. would not tolerate unrestricted submarine warfare, in violation of international law and U.S. ideas of human rights. Wilson was under pressure from former president Theodore Roosevelt
Theodore Roosevelt
Theodore "Teddy" Roosevelt was the 26th President of the United States . He is noted for his exuberant personality, range of interests and achievements, and his leadership of the Progressive Movement, as well as his "cowboy" persona and robust masculinity...

, who denounced German acts as "piracy". Wilson's desire to have a seat at negotiations at war's end to advance the League of Nations
League of Nations
The League of Nations was an intergovernmental organization founded as a result of the Paris Peace Conference that ended the First World War. It was the first permanent international organization whose principal mission was to maintain world peace...

 also played a role in the eventual decision to join the war. Wilson's Secretary of State, William Jennings Bryan
William Jennings Bryan
William Jennings Bryan was an American politician in the late-19th and early-20th centuries. He was a dominant force in the liberal wing of the Democratic Party, standing three times as its candidate for President of the United States...

, whose opinions had been ignored, resigned in 1915, as he could no longer support the president's policy. Public opinion was angered at suspected German sabotage of Black Tom
Black Tom explosion
The Black Tom explosion on July 30, 1916 in Jersey City, New Jersey was an act of sabotage on American ammunition supplies by German agents to prevent the materiel from being used by the Allies in World War I.- Black Tom Island :...

 in Jersey City, New Jersey
Jersey City, New Jersey
Jersey City is the seat of Hudson County, New Jersey, United States.Part of the New York metropolitan area, Jersey City lies between the Hudson River and Upper New York Bay across from Lower Manhattan and the Hackensack River and Newark Bay...

, and the Kingsland Explosion
Kingsland Explosion
The Kingsland Explosion was an incident that took place during World War I at a munitions factory in Lyndhurst, New Jersey.Soon after its outbreak in 1914 World War I settled in the West into an almost static line of trenches with the principal Allied armies facing the forces of Germany and...

.

In January 1917, Germany resumed unrestricted submarine warfare. The German Foreign Minister, in the Zimmermann Telegram
Zimmermann Telegram
The Zimmermann Telegram was a 1917 diplomatic proposal from the German Empire to Mexico to make war against the United States. The proposal was caught by the British before it could get to Mexico. The revelation angered the Americans and led in part to a U.S...

, told Mexico that U.S. entry was likely once unrestricted submarine warfare began, and invited Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

 to join the war as Germany's ally against the United States. In return, the Germans would send Mexico money and help it recover the territories of Texas, New Mexico, and Arizona that Mexico had lost during the Mexican-American War 70 years earlier. Wilson released the Zimmerman note to the public, and Americans saw it as casus belli— a cause for war.

U.S. declaration of war on Germany


After the sinking of seven U.S. merchant ships by submarines and the publication of the Zimmerman telegram, Wilson called for war on Germany, which the U.S. Congress declared on 6 April 1917.
First active U.S. participation

The United States was never formally a member of the Allies but became a self-styled "Associated Power". The United States had a small army, but, after the passage of the Selective Service Act
Selective Service Act of 1917
The Selective Service Act or Selective Draft Act was passed by the Congress of the United States on May 18, 1917. It was envisioned in December 1916 and brought to President Woodrow Wilson's attention shortly after the break in relations with Germany in February 1917...

, it drafted 2.8 million men, and by summer 1918 was sending 10,000 fresh soldiers to France every day. In 1917, the U.S. Congress gave U.S. citizenship to Puerto Ricans when they were drafted to participate in World War I, as part of the Jones Act
Jones-Shafroth Act
The Jones–Shafroth Act was a 1917 Act of the United States Congress by which Puerto Ricans were collectively made U.S. citizens, the people of Puerto Rico were empowered to have a popularly-elected Senate, established a bill of rights, and authorized the election of a Resident Commissioner to a...

. Germany had miscalculated, believing it would be many more months before American soldiers would arrive and that their arrival could be stopped by U-boats.

The United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 sent a battleship group
United States Battleship Division Nine (World War I)
United States Battleship Division Nine was a division of four, later five, dreadnought battleships of the United States Navy's Atlantic Fleet that constituted the American contribution to the British Grand Fleet during World War I. Although the U.S. entered the war on 6 April 1917, hesitation among...

 to Scapa Flow
Scapa Flow
right|thumb|Scapa Flow viewed from its eastern endScapa Flow is a body of water in the Orkney Islands, Scotland, United Kingdom, sheltered by the islands of Mainland, Graemsay, Burray, South Ronaldsay and Hoy. It is about...

 to join with the British Grand Fleet, destroyers to Queenstown
Cobh
Cobh is a seaport town on the south coast of County Cork, Ireland. Cobh is on the south side of Great Island in Cork Harbour. Facing the town are Spike Island and Haulbowline Island...

, Ireland, and submarines to help guard convoys. Several regiments of U.S. Marines were also dispatched to France. The British and French wanted U.S. units used to reinforce their troops already on the battle lines and not waste scarce shipping on bringing over supplies. The U.S. rejected the first proposition and accepted the second. General John J. Pershing
John J. Pershing
John Joseph "Black Jack" Pershing, GCB , was a general officer in the United States Army who led the American Expeditionary Forces in World War I...

, American Expeditionary Forces (AEF) commander, refused to break up U.S. units to be used as reinforcements for British Empire and French units. As an exception, he did allow African-American combat regiments to be used in French divisions. The Harlem Hellfighters
Harlem Hellfighters
The 369th Infantry Regiment, formerly the 15th New York National Guard Regiment, was an infantry regiment of the United States Army that saw action in World War I and World War II. The 369th Infantry is known for being the first African-American regiment to serve with the American Expeditionary...

 fought as part of the French 16th Division, earning a unit Croix de Guerre
Croix de guerre
The Croix de guerre is a military decoration of France. It was first created in 1915 and consists of a square-cross medal on two crossed swords, hanging from a ribbon with various degree pins. The decoration was awarded during World War I, again in World War II, and in other conflicts...

 for their actions at Chateau-Thierry, Belleau Wood, and Sechault. AEF doctrine called for the use of frontal assaults, which had long since been discarded by British Empire and French commanders because of the large loss of life.

Austrian offer of separate peace

In 1917, Emperor Charles I of Austria secretly attempted separate peace negotiations with Clemenceau, with his wife's brother Sixtus
Prince Sixtus of Bourbon-Parma
Prince Sixtus of Bourbon-Parma was a Prince of the Duchy of Parma, a Belgian officer in the First World War, and the central figure in the Sixtus Affair.- Biography :Sixtus was a son of the last Duke of Parma, Robert I and his...

 in Belgium as an intermediary, without the knowledge of Germany. When the negotiations failed, his attempt was revealed to Germany, resulting in a diplomatic catastrophe.

German Spring Offensive of 1918

German General Erich Ludendorff
Erich Ludendorff
Erich Friedrich Wilhelm Ludendorff was a German general, victor of Liège and of the Battle of Tannenberg...

 drew up plans (codenamed
Code name
A code name or cryptonym is a word or name used clandestinely to refer to another name or word. Code names are often used for military purposes, or in espionage...

 Operation Michael
Operation Michael
Operation Michael was a First World War German military operation that began the Spring Offensive on 21 March 1918. It was launched from the Hindenburg Line, in the vicinity of Saint-Quentin, France...

) for the 1918 offensive on the Western Front. The Spring Offensive sought to divide the British and French forces with a series of feints and advances. The German leadership hoped to strike a decisive blow before significant U.S. forces arrived. The operation commenced on 21 March 1918 with an attack on British forces near Amiens
Amiens
Amiens is a city and commune in northern France, north of Paris and south-west of Lille. It is the capital of the Somme department in Picardy...

. German forces achieved an unprecedented advance of 60 kilometres (37.3 mi).

British and French trenches were penetrated using novel infiltration tactics
Infiltration tactics
In warfare, infiltration tactics involve small, lightly equipped infantry forces attacking enemy rear areas while bypassing enemy front line strongpoints and isolating them for attack by follow-up troops with heavier weapons.-Development during World War I:...

, also named Hutier tactics, after General Oskar von Hutier
Oskar von Hutier
Oskar von Hutier was one of Imperial Germany's most successful and innovative generals of World War I.-Biography:Hutier was born in Erfurt, in the Prussian Province of Saxony...

. Previously, attacks had been characterised by long artillery bombardments and massed assaults. However, in the Spring Offensive of 1918, Ludendorff used artillery only briefly and infiltrated small groups of infantry at weak points. They attacked command and logistics areas and bypassed points of serious resistance. More heavily armed infantry then destroyed these isolated positions. German success relied greatly on the element of surprise.

The front moved to within 120 kilometres (74.6 mi) of Paris. Three heavy Krupp
Krupp
The Krupp family , a prominent 400-year-old German dynasty from Essen, have become famous for their steel production and for their manufacture of ammunition and armaments. The family business, known as Friedrich Krupp AG Hoesch-Krupp, was the largest company in Europe at the beginning of the 20th...

 railway gun
Railway gun
A railway gun, also called a railroad gun, is a large artillery piece, often surplus naval ordnance, mounted on, transported by, and fired from a specially designed railway wagon. Many countries have built railway guns, but the best known are the large Krupp-built pieces used by Germany in World...

s fired 183 shells on the capital, causing many Parisians to flee. The initial offensive was so successful that Kaiser Wilhelm II declared 24 March a national holiday
Public holiday
A public holiday, national holiday or legal holiday is a holiday generally established by law and is usually a non-working day during the year....

. Many Germans thought victory was near. After heavy fighting, however, the offensive was halted. Lacking tanks or motorised artillery
Self-propelled artillery
Self-propelled artillery vehicles are combat vehicles armed with artillery. Within the term are covered self-propelled guns and rocket artillery...

, the Germans were unable to consolidate their gains. This situation was not helped by the supply lines now being stretched as a result of their advance. The sudden stop was also a result of the four Australian Imperial Force
Australian Imperial Force
The Australian Imperial Force was the name given to all-volunteer Australian Army forces dispatched to fight overseas during World War I and World War II.* First Australian Imperial Force * Second Australian Imperial Force...

 (AIF) divisions that were "rushed" down, thus doing what no other army had done: stopping the German advance in its tracks. During that time the first Australian division was hurriedly sent north again to stop the second German breakthrough.
General Foch
Ferdinand Foch
Ferdinand Foch , GCB, OM, DSO was a French soldier, war hero, military theorist, and writer credited with possessing "the most original and subtle mind in the French army" in the early 20th century. He served as general in the French army during World War I and was made Marshal of France in its...

 pressed to use the arriving American troops as individual replacements. Pershing sought instead to field American units as an independent force. These units were assigned to the depleted French and British Empire commands on 28 March. A Supreme War Council of Allied forces was created at the Doullens Conference
Doullens conference
The Doullens Conference was held in Doullens, France on March 26, 1918 between French and British military leaders. The purpose of the conference was to better coordinate the British and French military operations on the Western Front.- Cause :...

 on 5 November 1917. General Foch was appointed as supreme commander of the allied forces. Haig, Petain, and Pershing retained tactical control of their respective armies; Foch assumed a coordinating rather than a directing role, and the British, French, and U.S. commands operated largely independently.

Following Operation Michael, Germany launched Operation Georgette against the northern English Channel
English Channel
The English Channel , often referred to simply as the Channel, is an arm of the Atlantic Ocean that separates southern England from northern France, and joins the North Sea to the Atlantic. It is about long and varies in width from at its widest to in the Strait of Dover...

 ports. The Allies halted the drive after limited territorial gains by Germany. The German Army to the south then conducted Operations Blücher and Yorck
Third Battle of the Aisne
The Third Battle of the Aisne was a battle of the German Spring Offensive during World War I that focused on capturing the Chemin des Dames Ridge before the American Expeditionary Force could arrive completely in France. It was one of a series of desperate offensives, known as the Kaiserschlacht,...

, pushing broadly towards Paris. Operation Marne was launched on 15 July, attempting to encircle Reims
Reims
Reims , a city in the Champagne-Ardenne region of France, lies east-northeast of Paris. Founded by the Gauls, it became a major city during the period of the Roman Empire....

 and beginning the Second Battle of the Marne
Second Battle of the Marne
The Second Battle of the Marne , or Battle of Reims was the last major German Spring Offensive on the Western Front during the First World War. The German attack failed when an Allied counterattack led by France overwhelmed the Germans, inflicting severe casualties...

. The resulting counterattack, starting the Hundred Days Offensive
Hundred Days Offensive
The Hundred Days Offensive was the final period of the First World War, during which the Allies launched a series of offensives against the Central Powers on the Western Front from 8 August to 11 November 1918, beginning with the Battle of Amiens. The offensive forced the German armies to retreat...

, marked the first successful Allied offensive of the war.

By 20 July the Germans were back across the Marne at their Kaiserschlacht starting lines, having achieved nothing. Following this last phase of the war in the West, the German Army never regained the initiative. German casualties between March and April 1918 were 270,000, including many highly trained storm troopers.

Meanwhile, Germany was falling apart at home. Anti-war
Anti-war
An anti-war movement is a social movement, usually in opposition to a particular nation's decision to start or carry on an armed conflict, unconditional of a maybe-existing just cause. The term can also refer to pacifism, which is the opposition to all use of military force during conflicts. Many...

 marches became frequent and morale in the army fell. Industrial output was 53 percent of 1913 levels.

New states under war zone

In the late spring of 1918, three new states were formed in the South Caucasus
South Caucasus
The South Caucasus is a geopolitical region located on the border of Eastern Europe and Southwest Asia also referred to as Transcaucasia, or The Trans-Caucasus...

: the Democratic Republic of Armenia
Democratic Republic of Armenia
The Democratic Republic of Armenia was the first modern establishment of an Armenian state...

, the Azerbaijan Democratic Republic
Azerbaijan Democratic Republic
The Azerbaijan Democratic Republic was the first successful attempt to establish a democratic and secular republic in the Muslim world . The ADR was founded on May 28, 1918 after the collapse of the Russian Empire that began with the Russian Revolution of 1917 by Azerbaijani National Council in...

, and the Democratic Republic of Georgia
Democratic Republic of Georgia
The Democratic Republic of Georgia , 1918–1921, was the first modern establishment of a Republic of Georgia.The DRG was created after the collapse of the Russian Empire that began with the Russian Revolution of 1917...

, which declared their independence from the Russian Empire. Two other minor entities were established, the Centrocaspian Dictatorship
Centrocaspian Dictatorship
The Central-Caspian Dictatorship , or the Centro-Caspian Dictatorship, was a short-lived anti-Soviet client state proclaimed in Baku, the capital of present-day Azerbaijan, during World War I...

 and South West Caucasian Republic (The former was liquidated by Azerbaijan in the autumn of 1918 and the latter by a joint Armenian-British task force in early 1919). With the withdrawal of the Russian armies from the Caucasus front in the winter of 1917-18, the three major republics braced for an imminent Ottoman advance, which commenced in the early months of 1918. Solidarity was briefly maintained when the Transcaucasian Federative Republic
Transcaucasian Democratic Federative Republic
The Transcaucasian Democratic Federative Republic , was a short-lived state composed of the modern-day countries of Armenia, Azerbaijan, and Georgia in the South Caucasus.-...

 was created in the spring of 1918 but collapsed in May, when the Georgians asked and received protection from Germany and the Azerbaijanis concluded a treaty with the Ottoman Empire that was more akin to a military alliance. Armenia was left to fend for itself and struggled for five months against the threat of a full-fledged occupation by the Ottoman Turks.

Allied victory: summer and autumn 1918

The Allied counteroffensive, known as the Hundred Days Offensive, began on 8 August 1918. The Battle of Amiens developed with III Corps British Fourth Army
British Fourth Army
The Fourth Army was a field army that formed part of the British Expeditionary Force during the First World War. The Fourth Army was formed on 5 February 1916 under the command of General Sir Henry Rawlinson to carry out the main British contribution to the Battle of the Somme.-History:The Fourth...

 on the left, the French First Army
French First Army
The First Army was a field army of France that fought during World War I and World War II. It was also active during the Cold War.-First World War:...

 on the right, and the Australian
Australian Corps
The Australian Corps was a World War I army corps that contained all five Australian infantry divisions serving on the Western Front. It was the largest corps fielded by the British Empire army in France...

 and Canadian Corps
Canadian Corps
The Canadian Corps was a World War I corps formed from the Canadian Expeditionary Force in September 1915 after the arrival of the 2nd Canadian Division in France. The corps was expanded by the addition of the 3rd Canadian Division in December 1915 and the 4th Canadian Division in August 1916...

 spearheading the offensive in the centre through Harbonnières
Harbonnières
Harbonnières is a commune in the Somme department in Picardie in northern France.-Geography:The commune is situated on the D337 road, some east of Amiens.-Population:-Places of interest:...

. It involved 414 tanks of the Mark IV
Mark I tank
The British Mark I was a tracked vehicle developed by the British Army during the First World War and the world's first combat tank. The Mark I entered service in August 1916, and was first used in action on the morning of 15 September 1916 during the Battle of Flers-Courcelette, of the Somme...

 and Mark V type, and 120,000 men. They advanced 12 kilometres (7.5 mi) into German-held territory in just seven hours. Erich Ludendorff referred to this day as the "Black Day of the German army".

The Australian-Canadian spearhead at Amiens, a battle that was the beginning of Germany’s downfall, helped pull forward the British armies to the north and the French armies to the south. On the British Fourth Army front at Amiens, after an advance as far as 14 miles (23 km), German resistance stiffened, and the battle there concluded. But the French Third Army lengthened the Amiens front on 10 August, when it was thrown in on the right of the French First Army, and advanced 4 miles (6 km), liberating Lassigny in fighting which lasted until 16 August. South of the French Third Army, General Charles Mangin
Charles Mangin
Charles Emmanuel Marie Mangin was a French general during World War I.-Early career:...

 (The Butcher) drove his French Tenth Army forward at Soissons on 20 August to capture eight thousand prisoners, two hundred guns, and the Aisne heights overlooking and menacing the German position north of the Vesle. Another "Black day", as described by Erich Ludendorff.

Meanwhile General Byng of the British Third Army, reporting that the enemy on his front was thinning in a limited withdrawal, was ordered to attack with 200 tanks towards Bapaume, opening the Battle of Albert
Battle of Albert (1918)
Battle of Albert was the third battle by that name fought during World War I, following the First Battle of Albert, and the Second Battle of Albert, with each of the series of three being fought roughly two years apart...

, with specific orders "To break the enemy's front, in order to outflank the enemy's present battle front" (opposite the British Fourth Army at Amiens). Allied leaders had now realised that to continue an attack after resistance had hardened was a waste of lives, and it was better to turn a line than to try to roll over it. They began to undertake attacks in quick order to take advantage of successful advances on the flanks, then broke them off when each attack lost its initial impetus.

The British Third Army's 15 miles (24 km) front north of Albert progressed after stalling for a day against the main resistance line to which the enemy had withdrawn. Rawlinson’s British Fourth Army was able to push its left flank forward between Albert and the Somme, straightening the line between the advanced positions of the Third Army and the Amiens front, which resulted in recapturing Albert at the same time. On 26 August the British First Army on the left of the Third Army was drawn into the battle, extending it northward to beyond Arras. The Canadian Corps, already back in the vanguard of the First Army, fought its way from Arras eastward 5 miles (8 km) astride the heavily defended Arras-Cambrai area before reaching the outer defences of the Hindenburg Line
Hindenburg Line
The Hindenburg Line was a vast system of defences in northeastern France during World War I. It was constructed by the Germans during the winter of 1916–17. The line stretched from Lens to beyond Verdun...

, breaching them on the 28 and 29 August. Bapaume fell on 29 August to the New Zealand Division of the Third Army, and the Australians, still leading the advance of the Fourth Army, were again able to push forward at Amiens to take Peronne and Mont Saint-Quentin on 31 August. Further south, the French First and Third Armies had slowly fought forward while the Tenth Army, which had by now crossed the Ailette and was east of the Chemin des Dames, neared the Alberich position of the Hindenburg Line. During the last week of August the pressure along a 70 miles (113 km) front against the enemy was heavy and unrelenting. From German accounts, "Each day was spent in bloody fighting against an ever and again on-storming enemy, and nights passed without sleep in retirements to new lines." Even to the north in Flanders
Flanders
Flanders is the community of the Flemings but also one of the institutions in Belgium, and a geographical region located in parts of present-day Belgium, France and the Netherlands. "Flanders" can also refer to the northern part of Belgium that contains Brussels, Bruges, Ghent and Antwerp...

 the British Second and Fifth Armies during August and September were able to make progress, taking prisoners and positions that had previously been denied them.
On 2 September the Canadian Corps
Canadian Corps
The Canadian Corps was a World War I corps formed from the Canadian Expeditionary Force in September 1915 after the arrival of the 2nd Canadian Division in France. The corps was expanded by the addition of the 3rd Canadian Division in December 1915 and the 4th Canadian Division in August 1916...

 outflanking of the Hindenburg line, with the breaching of the Wotan Position, made it possible for the Third Army to advance, which sent repercussions all along the Western Front. That same day Oberste Heeresleitung
Oberste Heeresleitung
The Oberste Heeresleitung or OHL was Germany's highest echelon of command of the German Army in World War I, while the Navy was led by the Seekriegsleitung or SKL ....

 (OHL) had no choice but to issue orders to six armies to withdraw back into the Hindenburg Line in the south, behind the Canal du Nord
Canal du Nord
The Canal du Nord is a long canal in northern France. The canal connects the Canal latéral à l'Oise at Pont-l'Évêque to the Sensée Canal at Arleux. The French government, in partnership with coal-mining companies in the Nord and Pas-de-Calais departments, developed the canal to help French coal...

 on the Canadian-First Army's front and back to a line east of the Lys in the north. This ceded without a fight the salient seized the previous April. According to Ludendorff
Erich Ludendorff
Erich Friedrich Wilhelm Ludendorff was a German general, victor of Liège and of the Battle of Tannenberg...

 “We had to admit the necessity ...to withdraw the entire front from the Scarpe to the Vesle.”

In nearly four weeks of fighting beginning 8 August, over 100,000 German prisoners were taken, 75,000 by the BEF and the rest by the French. As of "The Black Day of the German Army", the German High Command realised the war was lost and made attempts to reach a satisfactory end. The day after that battle Ludenforff told Colonel Mertz: "We cannot win the war any more, but we must not lose it either." On 11 August he offered his resignation to the Kaiser, who refused it, replying, "I see that we must strike a balance. We have nearly reached the limit of our powers of resistance. The war must be ended." On 13 August at Spa
Spa, Belgium
Spa is a municipality of Belgium. It lies in the country's Walloon Region and Province of Liège. It is situated in a valley in the Ardennes mountain chain, some southeast of Liège, and southwest of Aachen. As of 1 January 2006, Spa had a total population of 10,543...

, Hindenburg, Ludendorff, the Chancellor, and Foreign Minister Hintz agreed that the war could not be ended militarily, and on the following day the German Crown Council decided that victory in the field was now most improbable. Austria and Hungary warned that they could only continue the war until December, and Ludendorff recommended immediate peace negotiations, to which the Kaiser responded by instructing Hintz to seek the mediation of the Queen of the Netherlands. Prince Rupprecht warned Prince Max of Baden: "Our military situation has deteriorated so rapidly that I no longer believe we can hold out over the winter; it is even possible that a catastrophe will come earlier." On 10 September Hindenburg urged peace moves to Emperor Charles of Austria, and Germany appealed to the Netherlands for mediation. On 14 September Austria sent a note to all belligerents and neutrals suggesting a meeting for peace talks on neutral soil, and on 15 September Germany made a peace offer to Belgium. Both peace offers were rejected, and on 24 September OHL
Oberste Heeresleitung
The Oberste Heeresleitung or OHL was Germany's highest echelon of command of the German Army in World War I, while the Navy was led by the Seekriegsleitung or SKL ....

 informed the leaders in Berlin that armistice talks were inevitable.

September saw the Germans continuing to fight strong rear-guard actions and launching numerous counterattacks on lost positions, but only a few succeeded, and then only temporarily. Contested towns, villages, heights, and trenches in the screening positions and outposts of the Hindenburg Line continued to fall to the Allies, with the BEF alone taking 30,441 prisoners in the last week of September. Further small advances eastward would follow the Third Army's victory at Ivincourt on 12 September, the Fourth Army's at Epheny on 18 September, and the French gain of Essigny-le-Grand
Essigny-le-Grand
Essigny-le-Grand is a commune in the Aisne department in Picardy in northern France.-Population:-References:*...

 a day later. On 24 September a final assault by both the British and French on a 4 miles (6.4 km) front would come within 2 miles (3.2 km) of St. Quentin. With the outposts and preliminary defensive lines of the Siegfried and Alberich Positions eliminated, the Germans were now completely back in the Hindenburg Line. With the Wotan position of that line already breached and the Siegfried position in danger of being turned from the north, the time had now come for an Allied assault on the whole length of the line.

The Allied attack on the Hindenburg Line
Meuse-Argonne Offensive
The Meuse-Argonne Offensive, or Maas-Argonne Offensive, also called the Battle of the Argonne Forest, was a part of the final Allied offensive of World War I that stretched along the entire western front.-Overview:...

, begun on 26 September, included U.S. soldiers. The still-green American troops suffered problems coping with supply trains for large units on a difficult landscape. The following week cooperating French and American units broke through in Champagne
Champagne, France
Champagne is a historic province in the northeast of France, now best known for the sparkling white wine that bears its name.Formerly ruled by the counts of Champagne, its western edge is about 100 miles east of Paris. The cities of Troyes, Reims, and Épernay are the commercial centers of the area...

 at the Battle of Blanc Mont Ridge
Battle of Blanc Mont Ridge
The Battle of Blanc Mont Ridge occurred during World War I, northeast of Reims, in Champagne, France. In the battle, the U.S. Army's 2nd Infantry Division and the 36th Infantry Division opposed the German 200th and 213th Divisions, along with portions of six additional German divisions...

, forcing the Germans off the commanding heights, and closing towards the Belgian frontier. The last Belgian town to be liberated before the armistice was Ghent, which the Germans held as a pivot until the Allies brought up artillery. The German army had to shorten its front and use the Dutch frontier as an anchor to fight rear-guard actions.

When Bulgaria signed a separate armistice on 29 September, the Allies gained control of Serbia and Greece. Ludendorff, having been under great stress for months, suffered something similar to a breakdown. It was evident that Germany could no longer mount a successful defence.

Meanwhile, news of Germany's impending military defeat spread throughout the German armed forces. The threat of mutiny was rife. Admiral Reinhard Scheer
Reinhard Scheer
Reinhard Scheer was an Admiral in the German Kaiserliche Marine. Scheer joined the navy in 1879 as an officer cadet; he progressed through the ranks, commanding cruisers and battleships, as well as major staff positions on land. At the outbreak of World War I, Scheer was the commander of the II...

 and Ludendorff decided to launch a last attempt to restore the "valour" of the German Navy. Knowing the government of Prince Maximilian of Baden
Prince Maximilian of Baden
Maximilian of Baden was a German prince and politician...

 would veto any such action, Ludendorff decided not to inform him. Nonetheless, word of the impending assault reached sailors at Kiel
Kiel
Kiel is the capital and most populous city in the northern German state of Schleswig-Holstein, with a population of 238,049 .Kiel is approximately north of Hamburg. Due to its geographic location in the north of Germany, the southeast of the Jutland peninsula, and the southwestern shore of the...

. Many, refusing to be part of a naval offensive which they believed to be suicidal, rebelled and were arrested. Ludendorff took the blame; the Kaiser dismissed him on 26 October. The collapse of the Balkans meant that Germany was about to lose its main supplies of oil and food. Its reserves had been used up, even as U.S. troops kept arriving at the rate of 10,000 per day.

Having suffered over 6 million casualties, Germany moved towards peace. Prince Maximilian of Baden
Prince Maximilian of Baden
Maximilian of Baden was a German prince and politician...

 took charge of a new government as Chancellor of Germany to negotiate with the Allies. Telegraphic negotiations with President Wilson began immediately, in the vain hope that he would offer better terms than the British and French. Instead Wilson demanded the abdication of the Kaiser. There was no resistance when the social democrat Philipp Scheidemann
Philipp Scheidemann
Philipp Scheidemann was a German Social Democratic politician, who proclaimed the Republic on 9 November 1918, and who became the second Chancellor of the Weimar Republic....

 on 9 November declared Germany to be a republic. Imperial Germany was dead; a new Germany had been born: the Weimar Republic
Weimar Republic
The Weimar Republic is the name given by historians to the parliamentary republic established in 1919 in Germany to replace the imperial form of government...

.

Armistices and capitulations

The collapse of the Central Powers came swiftly. Bulgaria was the first to sign an armistice, on 29 September 1918 at Saloniki. On 30 October, the Ottoman Empire capitulated at Moudros
Moudros
Moudros is a town and a former municipality on the island of Lemnos, North Aegean, Greece. Since the 2011 local government reform it is part of the municipality Lemnos, of which it is a municipal unit. It covers the entire eastern peninsula of the island, with a land area of 185.127 km²,...

 (Armistice of Mudros
Armistice of Mudros
The Armistice of Moudros , concluded on 30 October 1918, ended the hostilities in the Middle Eastern theatre between the Ottoman Empire and the Allies of World War I...

).

On 24 October, the Italians began a push which rapidly recovered territory lost after the Battle of Caporetto
Battle of Caporetto
The Battle of Caporetto , took place from 24 October to 19 November 1917, near the town of Kobarid , on the Austro-Italian front of World War I...

. This culminated in the Battle of Vittorio Veneto
Battle of Vittorio Veneto
The Battle of Vittorio Veneto was fought between 24 October and 3 November 1918, near Vittorio Veneto, during the Italian Campaign of World War I...

, which marked the end of the Austro-Hungarian Army as an effective fighting force. The offensive also triggered the disintegration of the Austro-Hungarian Empire. During the last week of October, declarations of independence were made in Budapest, Prague, and Zagreb. On 29 October, the imperial authorities asked Italy for an armistice. But the Italians continued advancing, reaching Trento, Udine, and Trieste. On 3 November Austria–Hungary sent a flag of truce
White flag
White flags have had different meanings throughout history and depending on the locale.-Flag of temporary truce in order to parley :...

 to ask for an Armistice
Armistice
An armistice is a situation in a war where the warring parties agree to stop fighting. It is not necessarily the end of a war, but may be just a cessation of hostilities while an attempt is made to negotiate a lasting peace...

. The terms, arranged by telegraph with the Allied Authorities in Paris, were communicated to the Austrian commander and accepted. The Armistice with Austria was signed in the Villa Giusti, near Padua
Padua
Padua is a city and comune in the Veneto, northern Italy. It is the capital of the province of Padua and the economic and communications hub of the area. Padua's population is 212,500 . The city is sometimes included, with Venice and Treviso, in the Padua-Treviso-Venice Metropolitan Area, having...

, on 3 November. Austria and Hungary signed separate armistices following the overthrow of the Habsburg Monarchy
Habsburg Monarchy
The Habsburg Monarchy covered the territories ruled by the junior Austrian branch of the House of Habsburg , and then by the successor House of Habsburg-Lorraine , between 1526 and 1867/1918. The Imperial capital was Vienna, except from 1583 to 1611, when it was moved to Prague...

.

Following the outbreak of the German Revolution of 1918–1919, a republic was proclaimed on 9 November. The Kaiser
Kaiser
Kaiser is the German title meaning "Emperor", with Kaiserin being the female equivalent, "Empress". Like the Russian Czar it is directly derived from the Latin Emperors' title of Caesar, which in turn is derived from the personal name of a branch of the gens Julia, to which Gaius Julius Caesar,...

 fled to the Netherlands. On 11 November an armistice with Germany was signed in a railroad carriage at Compiègne
Compiègne
Compiègne is a city in northern France. It is designated municipally as a commune within the département of Oise.The city is located along the Oise River...

. At 11 a.m. on 11 November 1918 — "the eleventh hour of the eleventh day of the eleventh month" — a ceasefire came into effect. Opposing armies on the Western Front began to withdraw from their positions. Canadian Private George Lawrence Price
George Lawrence Price
Private George Lawrence Price was a Canadian soldier. He is traditionally recognized as the last soldier of the British Empire to be killed during the First World War....

 is traditionally regarded as the last soldier killed in the Great War: he was shot by a German sniper at 10:57 and died at 10:58.

Allied superiority and the stab-in-the-back legend, November 1918

In November 1918 the Allies had ample supplies of men and materiel
Materiel
Materiel is a term used in English to refer to the equipment and supplies in military and commercial supply chain management....

 to invade Germany. Yet at the time of the armistice, no Allied force had crossed the German frontier; the Western Front was still almost 900 mi (1,448.4 km) from Berlin; and the Kaiser's armies had retreated from the battlefield in good order. These factors enabled Hindenburg and other senior German leaders to spread the story that their armies had not really been defeated. This resulted in the stab-in-the-back legend, which attributed Germany's defeat not to its inability to continue fighting (even though up to a million soldiers were suffering from the 1918 flu pandemic and unfit to fight), but to the public's failure to respond to its "patriotic calling" and the supposed intentional sabotage of the war effort, particularly by Jews, Socialists, and Bolsheviks.

A formal state of war between the two sides persisted for another seven months, until the signing of the Treaty of Versailles
Treaty of Versailles
The Treaty of Versailles was one of the peace treaties at the end of World War I. It ended the state of war between Germany and the Allied Powers. It was signed on 28 June 1919, exactly five years after the assassination of Archduke Franz Ferdinand. The other Central Powers on the German side of...

 with Germany on 28 June 1919. Later treaties with Austria, Hungary, Bulgaria, and the Ottoman Empire were signed. However, the negotiation of the latter treaty with the Ottoman Empire was followed by strife (the Turkish War of Independence
Turkish War of Independence
The Turkish War of Independence was a war of independence waged by Turkish nationalists against the Allies, after the country was partitioned by the Allies following the Ottoman Empire's defeat in World War I...

), and a final peace treaty between the Allied Powers and the country that would shortly become the Republic of Turkey was not signed until 24 July 1923, at Lausanne
Treaty of Lausanne
The Treaty of Lausanne was a peace treaty signed in Lausanne, Switzerland on 24 July 1923, that settled the Anatolian and East Thracian parts of the partitioning of the Ottoman Empire. The treaty of Lausanne was ratified by the Greek government on 11 February 1924, by the Turkish government on 31...

.

Some war memorial
War memorial
A war memorial is a building, monument, statue or other edifice to celebrate a war or victory, or to commemorate those who died or were injured in war.-Historic usage:...

s date the end of the war as being when the Versailles Treaty was signed in 1919, which was when many of the troops serving abroad finally returned to their home countries; by contrast, most commemorations of the war's end concentrate on the armistice of 11 November 1918. Legally, the formal peace treaties were not complete until the last, the Treaty of Lausanne, was signed. Under its terms, the Allied forces divested Constantinople
Constantinople
Constantinople was the capital of the Roman, Eastern Roman, Byzantine, Latin, and Ottoman Empires. Throughout most of the Middle Ages, Constantinople was Europe's largest and wealthiest city.-Names:...

 on 23 August 1923.

Technology

The First World War began as a clash of 20th-century technology
Technology
Technology is the making, usage, and knowledge of tools, machines, techniques, crafts, systems or methods of organization in order to solve a problem or perform a specific function. It can also refer to the collection of such tools, machinery, and procedures. The word technology comes ;...

 and 19th-century tactics
Military tactics
Military tactics, the science and art of organizing an army or an air force, are the techniques for using weapons or military units in combination for engaging and defeating an enemy in battle. Changes in philosophy and technology over time have been reflected in changes to military tactics. In...

, with the inevitably large ensuing casualties. By the end of 1917, however, the major armies, now numbering millions of men, had modernised and were making use of telephone, wireless communication
Wireless
Wireless telecommunications is the transfer of information between two or more points that are not physically connected. Distances can be short, such as a few meters for television remote control, or as far as thousands or even millions of kilometers for deep-space radio communications...

, armoured cars, tanks,, and aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

. Infantry formations were reorganised, so that 100-man companies were no longer the main unit of manoeuvre; instead, squads of 10 or so men, under the command of a junior NCO, were favoured.

Artillery also underwent a revolution. In 1914, cannons were positioned in the front line and fired directly at their targets. By 1917, indirect fire
Indirect fire
Indirect fire means aiming and firing a projectile in a high trajectory without relying on a direct line of sight between the gun and its target, as in the case of direct fire...

 with guns (as well as mortars and even machine guns) was commonplace, using new techniques for spotting and ranging, notably aircraft and the often overlooked field telephone
Field telephone
Field telephones are mobile telephones intended for military use, designed to withstand wartime conditions. They can draw power from their own battery, from a telephone exchange , or from an external power source. Some need no battery, being sound-powered telephones.Field telephones were first used...

. Counter-battery
Counter-battery fire
Counter-battery fire is a type of mission assigned to military artillery forces, which are given the task of locating and firing upon enemy artillery.-Background:...

 missions became commonplace, also, and sound detection was used to locate enemy batteries.

Germany was far ahead of the Allies in utilising heavy indirect fire. She employed 150 and 210 mm howitzer
Howitzer
A howitzer is a type of artillery piece characterized by a relatively short barrel and the use of comparatively small propellant charges to propel projectiles at relatively high trajectories, with a steep angle of descent...

s in 1914, when the typical French and British guns were only 75 and 105 mm. The British had a 6 inch (152 mm) howitzer, but it was so heavy it had to be hauled to the field in pieces and assembled. Germans also fielded Austrian 305 mm and 420 mm guns, and already by the beginning of the war had inventories of various calibers of Minenwerfer
Minenwerfer
Minenwerfer is the German name for a class of short range mortars used extensively during the First World War by the German Army...

 ideally suited for trench warfare.

Much of the combat involved trench warfare
Trench warfare
Trench warfare is a form of occupied fighting lines, consisting largely of trenches, in which troops are largely immune to the enemy's small arms fire and are substantially sheltered from artillery...

, in which hundreds often died for each yard gained. Many of the deadliest battles in history occurred during the First World War. Such battles include Ypres, the Marne
First Battle of the Marne
The Battle of the Marne was a First World War battle fought between 5 and 12 September 1914. It resulted in an Allied victory against the German Army under Chief of Staff Helmuth von Moltke the Younger. The battle effectively ended the month long German offensive that opened the war and had...

, Cambrai, the Somme, Verdun
Battle of Verdun
The Battle of Verdun was one of the major battles during the First World War on the Western Front. It was fought between the German and French armies, from 21 February – 18 December 1916, on hilly terrain north of the city of Verdun-sur-Meuse in north-eastern France...

, and Gallipoli. The Germans employed the Haber process
Haber process
The Haber process, also called the Haber–Bosch process, is the nitrogen fixation reaction of nitrogen gas and hydrogen gas, over an enriched iron or ruthenium catalyst, which is used to industrially produce ammonia....

 of nitrogen fixation
Nitrogen fixation
Nitrogen fixation is the natural process, either biological or abiotic, by which nitrogen in the atmosphere is converted into ammonia . This process is essential for life because fixed nitrogen is required to biosynthesize the basic building blocks of life, e.g., nucleotides for DNA and RNA and...

 to provide their forces with a constant supply of gunpowder, despite the British naval blockade. Artillery was responsible for the largest number of casualties and consumed vast quantities of explosives. The large number of head wounds caused by exploding shells and fragmentation
Fragmentation (weaponry)
Fragmentation is the process by which the casing of an artillery shell, bomb, grenade, etc. is shattered by the detonating high explosive filling. The correct technical terminology for these casing pieces is fragments , although shards or splinters can be used for non-preformed fragments...

 forced the combatant nations to develop the modern steel helmet
Helmet
A helmet is a form of protective gear worn on the head to protect it from injuries.Ceremonial or symbolic helmets without protective function are sometimes used. The oldest known use of helmets was by Assyrian soldiers in 900BC, who wore thick leather or bronze helmets to protect the head from...

, led by the French, who introduced the Adrian helmet
Adrian helmet
The M15 Adrian helmet was a combat helmet issued to the French Army during World War I. It was the first standard helmet of the French Army and was designed when millions of French troops were engaged in trench warfare, and head wounds became a frequent cause of battlefield casualties...

 in 1915. It was quickly followed by the Brodie helmet
Brodie helmet
The Brodie helmet, called Helmet, steel, Mark I helmet in Britain and the M1917 Helmet in the U.S., was a steel combat helmet designed and patented in 1915 by the Briton John Leopold Brodie...

, worn by British Imperial and U.S. troops, and in 1916 by the distinctive German Stahlhelm
Stahlhelm
Stahlhelm is German for "steel helmet". The Imperial German Army began to replace the traditional boiled-leather Pickelhaube with the Stahlhelm during World War I in 1916...

, a design, with improvements, still in use today.
"Gas! Gas! Quick, boys!... Fitting the clumsy helmets just in time; But someone still was yelling out and stumbling, And flound'ring like a man in fire or lime... Dim, through the misty panes and thick green light, As under a green sea, I saw him drowning."- Wilfred Owen
Wilfred Owen
Wilfred Edward Salter Owen MC was an English poet and soldier, one of the leading poets of the First World War...

,
DULCE ET DECORUM EST, 1917

The widespread use of chemical warfare was a distinguishing feature of the conflict. Gases used included chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...

, mustard gas and phosgene
Phosgene
Phosgene is the chemical compound with the formula COCl2. This colorless gas gained infamy as a chemical weapon during World War I. It is also a valued industrial reagent and building block in synthesis of pharmaceuticals and other organic compounds. In low concentrations, its odor resembles...

. Few war casualties were caused by gas, as effective countermeasures to gas attacks were quickly created, such as gas mask
Gas mask
A gas mask is a mask put on over the face to protect the wearer from inhaling airborne pollutants and toxic gases. The mask forms a sealed cover over the nose and mouth, but may also cover the eyes and other vulnerable soft tissues of the face. Some gas masks are also respirators, though the word...

s. The use of chemical warfare
Chemical warfare
Chemical warfare involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from Nuclear warfare and Biological warfare, which together make up NBC, the military acronym for Nuclear, Biological, and Chemical...

 and small-scale strategic bombing
Aerial bombing of cities
A species of strategic bombing, the aerial bombing of cities began in 1915 during World War I, grew to a vast scale in World War II, and continues to the present day. The development of aerial bombardment marked an increased capacity of armed forces to deliver explosive weapons in populated areas...

 were both outlawed by the 1907 Hague Conventions, and both proved to be of limited effectiveness, though they captured the public imagination.

The most powerful land-based weapons were railway gun
Railway gun
A railway gun, also called a railroad gun, is a large artillery piece, often surplus naval ordnance, mounted on, transported by, and fired from a specially designed railway wagon. Many countries have built railway guns, but the best known are the large Krupp-built pieces used by Germany in World...

s weighing hundreds of tons apiece. These were nicknamed Big Berthas
Big Bertha (Howitzer)
Big Bertha Bertha") is the name of a type of super-heavy howitzer developed by the famous armaments manufacturer Krupp in Germany on the eve of World War I...

, even though the namesake was not a railway gun. Germany developed the Paris Gun
Paris Gun
The Paris Gun was a German long-range siege gun used to bombard Paris during World War I. It was in service from March-August 1918. When it was first employed, Parisians believed they'd been bombed by a new type of high-altitude zeppelin, as neither the sound of an airplane nor a gun could be heard...

, able to bombard Paris from over 100 kilometres (62.1 mi), though shells were relatively light at 94 kilograms (210 lb). While the Allies also had railway guns, German models severely out-ranged and out-classed them.

Fixed-wing aircraft
Fixed-wing aircraft
A fixed-wing aircraft is an aircraft capable of flight using wings that generate lift due to the vehicle's forward airspeed. Fixed-wing aircraft are distinct from rotary-wing aircraft in which wings rotate about a fixed mast and ornithopters in which lift is generated by flapping wings.A powered...

 were first used militarily by the Italians in Libya on 23 October 1911 during the Italo-Turkish War
Italo-Turkish War
The Italo-Turkish or Turco-Italian War was fought between the Ottoman Empire and the Kingdom of Italy from September 29, 1911 to October 18, 1912.As a result of this conflict, Italy was awarded the Ottoman provinces of Tripolitania, Fezzan, and...

 for reconnaissance, soon followed by the dropping of grenades and aerial photography
Aerial photography
Aerial photography is the taking of photographs of the ground from an elevated position. The term usually refers to images in which the camera is not supported by a ground-based structure. Cameras may be hand held or mounted, and photographs may be taken by a photographer, triggered remotely or...

 the next year. By 1914 their military utility was obvious. They were initially used for reconnaissance
Reconnaissance
Reconnaissance is the military term for exploring beyond the area occupied by friendly forces to gain information about enemy forces or features of the environment....

 and ground attack
Close air support
In military tactics, close air support is defined as air action by fixed or rotary winged aircraft against hostile targets that are close to friendly forces, and which requires detailed integration of each air mission with fire and movement of these forces.The determining factor for CAS is...

. To shoot down enemy planes, anti-aircraft guns and fighter aircraft
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...

 were developed. Strategic bombers were created, principally by the Germans and British, though the former used Zeppelin
Zeppelin
A Zeppelin is a type of rigid airship pioneered by the German Count Ferdinand von Zeppelin in the early 20th century. It was based on designs he had outlined in 1874 and detailed in 1893. His plans were reviewed by committee in 1894 and patented in the United States on 14 March 1899...

s as well. Towards the end of the conflict, aircraft carrier
Aircraft carrier
An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...

s were used for the first time, with HMS Furious
HMS Furious (47)
HMS Furious was a modified cruiser built for the Royal Navy during the First World War. Designed to support the Baltic Project championed by the First Sea Lord of the Admiralty, Lord John Fisher, they were very lightly armoured and armed with only a few heavy guns. Furious was modified while...

 launching Sopwith Camels in a raid
Tondern raid
The Tondern raid, officially designated Operation F.7, was a British bombing raid mounted by the Royal Navy and Royal Air Force against the Imperial German Navy's airship base at Tondern in Germany. It was the first attack in history made by aircraft flying from a carrier flight deck. On 19 July...

 to destroy the Zeppelin hangars at Tondern in 1918.
Germany deployed U-boat
U-boat
U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...

s (submarines) after the war began. Alternating between restricted and unrestricted submarine warfare in the Atlantic, the Kaiserliche Marine
Kaiserliche Marine
The Imperial German Navy was the German Navy created at the time of the formation of the German Empire. It existed between 1871 and 1919, growing out of the small Prussian Navy and Norddeutsche Bundesmarine, which primarily had the mission of coastal defense. Kaiser Wilhelm II greatly expanded...

 employed them to deprive the British Isles of vital supplies. The deaths of British merchant sailors and the seeming invulnerability of U-boats led to the development of depth charges (1916), hydrophone
Hydrophone
A hydrophone is a microphone designed to be used underwater for recording or listening to underwater sound. Most hydrophones are based on a piezoelectric transducer that generates electricity when subjected to a pressure change...

s (passive sonar
Sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...

, 1917), blimp
Blimp
A blimp, or non-rigid airship, is a floating airship without an internal supporting framework or keel. A non-rigid airship differs from a semi-rigid airship and a rigid airship in that it does not have any rigid structure, neither a complete framework nor a partial keel, to help the airbag...

s, hunter-killer submarines (HMS R-1
British R class submarine
The R-class submarines were a class of 12 small British diesel-electric submarines built for the Royal Navy during World War I, and were forerunners of the modern hunter-killer submarines, in that they were designed specifically to attack and sink enemy submarines, their battery capacity and hull...

, 1917), forward-throwing anti-submarine weapon
Anti-submarine weapon
An anti-submarine weapon is any one of a range of devices that are intended to act against a submarine, and its crew, to destroy the vessel or to destroy or reduce its capability as a weapon of war...

s, and dipping hydrophones (the latter two both abandoned in 1918). To extend their operations, the Germans proposed supply submarines (1916). Most of these would be forgotten in the interwar period
Interwar period
Interwar period can refer to any period between two wars. The Interbellum is understood to be the period between the end of the Great War or First World War and the beginning of the Second World War in Europe....

mdash;until World War II revived the need.

Trenches, machine guns, air reconnaissance, barbed wire, and modern artillery with fragmentation shells
Shell (projectile)
A shell is a payload-carrying projectile, which, as opposed to shot, contains an explosive or other filling, though modern usage sometimes includes large solid projectiles properly termed shot . Solid shot may contain a pyrotechnic compound if a tracer or spotting charge is used...

 helped bring the battle lines of World War I to a stalemate. The British sought a solution with the creation of the tank and mechanised warfare. The first tanks were used during the Battle of the Somme on 15 September 1916. Mechanical reliability was an issue, but the experiment proved its worth. Within a year, the British were fielding tanks by the hundreds, and they showed their potential during the Battle of Cambrai in November 1917, by breaking the Hindenburg Line, while combined arms
Combined arms
Combined arms is an approach to warfare which seeks to integrate different branches of a military to achieve mutually complementary effects...

 teams captured 8000 enemy soldiers and 100 guns. The conflict also saw the introduction of Light automatic weapons
Light machine gun
A light machine gun is a machine gun designed to be employed by an individual soldier, with or without an assistant, as an infantry support weapon. Light machine guns are often used as squad automatic weapons.-Characteristics:...

 and submachine guns, such as the Lewis Gun
Lewis Gun
The Lewis Gun is a World War I–era light machine gun of American design that was perfected and widely used by the British Empire. It was first used in combat in World War I, and continued in service with a number of armed forces through to the end of the Korean War...

, the Browning automatic rifle
Browning Automatic Rifle
The Browning Automatic Rifle was a family of United States automatic rifles and light machine guns used by the United States and numerous other countries during the 20th century. The primary variant of the BAR series was the M1918, chambered for the .30-06 Springfield rifle cartridge and designed...

, and the Bergmann MP18.

Manned observation balloon
Observation balloon
Observation balloons are balloons that are employed as aerial platforms for intelligence gathering and artillery spotting. Their use began during the French Revolutionary Wars, reaching their zenith during World War I, and they continue in limited use today....

s, floating high above the trenches, were used as stationary reconnaissance platforms, reporting enemy movements and directing artillery. Balloons commonly had a crew of two, equipped with parachute
Parachute
A parachute is a device used to slow the motion of an object through an atmosphere by creating drag, or in the case of ram-air parachutes, aerodynamic lift. Parachutes are usually made out of light, strong cloth, originally silk, now most commonly nylon...

s., so that if there was an enemy air attack the crew could parachute to safety. (At the time, parachutes were too heavy to be used by pilots of aircraft (with their marginal power output), and smaller versions were not developed until the end of the war; they were also opposed by British leadership, who feared they might promote cowardice.)
Recognised for their value as observation platforms, balloons were important targets of enemy aircraft. To defend them against air attack, they were heavily protected by antiaircraft guns and patrolled by friendly aircraft; to attack them, unusual weapons such as air-to-air rockets were even tried. Thus, the reconnaissance value of blimps and balloons contributed to the development of air-to-air combat between all types of aircraft, and to the trench stalemate, because it was impossible to move large numbers of troops undetected. The Germans conducted air raids on England during 1915 and 1916 with airships, hoping to damage British morale and cause aircraft to be diverted from the front lines, and indeed the resulting panic led to the diversion of several squadrons of fighters from France.

Another new weapon, the flamethrower
Flamethrower
A flamethrower is a mechanical device designed to project a long controllable stream of fire.Some flamethrowers project a stream of ignited flammable liquid; some project a long gas flame. Most military flamethrowers use liquids, but commercial flamethrowers tend to use high-pressure propane and...

, was first used by the German army and later adopted by other forces. Although not of high tactical value, the flamethrower was a powerful, demoralising weapon that caused terror on the battlefield. It was a dangerous weapon to wield, as its heavy weight made operators vulnerable targets.

Trench railways
Trench railways
Trench Railways represented military adaptation of early 20th century railway technology to the problem of keeping soldiers supplied during the static trench warfare phase of World War I...

 evolved to supply the enormous quantities of food, water, and ammunition required to support large numbers of soldiers in areas where conventional transportation systems had been destroyed. Internal combustion engines and improved traction systems for automobiles and trucks/lorries eventually rendered trench railways obsolete.

Ottoman Empire

The ethnic cleansing
Ethnic cleansing
Ethnic cleansing is a purposeful policy designed by one ethnic or religious group to remove by violent and terror-inspiring means the civilian population of another ethnic orreligious group from certain geographic areas....

 of the Ottoman Empire's Christian population, with the most prominent among them being the deportation and massacres of Armenians
Armenians
Armenian people or Armenians are a nation and ethnic group native to the Armenian Highland.The largest concentration is in Armenia having a nearly-homogeneous population with 97.9% or 3,145,354 being ethnic Armenian....

 (similar policies were enacted against the Assyrians
Assyrian people
The Assyrian people are a distinct ethnic group whose origins lie in ancient Mesopotamia...

 and Ottoman Greeks
Ottoman Greeks
Ottoman Greeks were ethnic Greeks who lived in the Ottoman Empire , the Republic of Turkey's predecessor...

) during the final years of the Ottoman Empire is considered genocide
Genocide
Genocide is defined as "the deliberate and systematic destruction, in whole or in part, of an ethnic, racial, religious, or national group", though what constitutes enough of a "part" to qualify as genocide has been subject to much debate by legal scholars...

. The Ottomans saw the entire Armenian population as an enemy
Fifth column
A fifth column is a group of people who clandestinely undermine a larger group such as a nation from within.-Origin:The term originated with a 1936 radio address by Emilio Mola, a Nationalist General during the 1936–39 Spanish Civil War...

 that had chosen to side with Russia at the beginning of the war. In early 1915, a number of Armenians joined the Russian forces, and the Ottoman government used this as a pretext to issue the Tehcir Law
Tehcir Law
The Tehcir Law was passed by the Ottoman Parliament on May 27, 1915 and allegedly came into force on June 1, 1915, with publication in Takvim-i Vekayi, the official gazette of the Ottoman State...

 (Law on Deportation). This authorized the deportation of the Armenians from eastern provinces of the Empire to Syria between 1915 and 1917. The exact number of deaths is unknown: while Balakian gives a range of 250,000 to 1.5 million for the deaths of Armenians, the International Association of Genocide Scholars
International Association of Genocide Scholars
The International Association of Genocide Scholars is a global, interdisciplinary, non-partisan organization that seeks to further research and teaching about the nature, causes, and consequences of genocide, and advance policy studies on prevention of genocide. The Association, founded in 1994 by...

 estimates over 1 million. The government of Turkey has consistently rejected charges of genocide, arguing that those who died were victims of inter-ethnic fighting, famine, or disease during the First World War.

Russian Empire

Approximately 200,000 Germans living in Volhynia
Volhynia
Volhynia, Volynia, or Volyn is a historic region in western Ukraine located between the rivers Prypiat and Southern Bug River, to the north of Galicia and Podolia; the region is named for the former city of Volyn or Velyn, said to have been located on the Southern Bug River, whose name may come...

 and about 600,000 Jews were deported by the Russian authorities. In 1916, an order was issued to deport around 650,000 Volga Germans to the east as well, but the Russian Revolution prevented this from being carried out. Many pogrom
Pogrom
A pogrom is a form of violent riot, a mob attack directed against a minority group, and characterized by killings and destruction of their homes and properties, businesses, and religious centres...

s accompanied the Revolution of 1917 and the ensuing Russian Civil War
Russian Civil War
The Russian Civil War was a multi-party war that occurred within the former Russian Empire after the Russian provisional government collapsed to the Soviets, under the domination of the Bolshevik party. Soviet forces first assumed power in Petrograd The Russian Civil War (1917–1923) was a...

, 60,000–200,000 civilian Jews were killed in the atrocities throughout the former Russian Empire.

"Rape of Belgium"

In Belgium, German troops, in fear of French and Belgian guerrilla fighters, or francs-tireurs
Francs-tireurs
Francs-tireurs – literally "free shooters" – was used to describe irregular military formations deployed by France during the early stages of the Franco-Prussian War...

, massacred townspeople in Andenne
Andenne
Andenne is a Belgian municipality located in the Walloon province of Namur. On January 1, 2006 Andenne had a total population of 25,240. The total area is 86.17 km² which gives a population density of 292 inhabitants per km². The city extends on both sides of the river Meuse...

 (211 dead), Tamines (384 dead), and Dinant
Dinant
Dinant is a Walloon city and municipality located on the River Meuse in the Belgian province of Namur, Belgium. The Dinant municipality includes the old communes of Anseremme, Bouvignes-sur-Meuse, Dréhance, Falmagne, Falmignoul, Foy-Notre-Dame, Furfooz, Lisogne, Sorinnes, and Thynes.-Origins to...

 (612 dead). On 25 August 1914, the Germans set fire to the town of Leuven
Leuven
Leuven is the capital of the province of Flemish Brabant in the Flemish Region, Belgium...

, burned the library containing about 230,000 books, killed 209 civilians, and forced 42,000 to evacuate. These actions brought worldwide condemnation.

Soldiers' experiences

The soldiers of the war were initially volunteers, except for those of Italy, but increasingly were conscripted
Conscription
Conscription is the compulsory enlistment of people in some sort of national service, most often military service. Conscription dates back to antiquity and continues in some countries to the present day under various names...

 into service. Britain's Imperial War Museum
Imperial War Museum
Imperial War Museum is a British national museum organisation with branches at five locations in England, three of which are in London. The museum was founded during the First World War in 1917 and intended as a record of the war effort and sacrifice of Britain and her Empire...

 has collected more than 2,500 recordings of soldiers' personal accounts, and selected transcripts, edited by military author Max Arthur
Max Arthur
Max Arthur is an oral and military historian and author who specialises in first-hand recollections of historical events, particularly the two World Wars of the twentieth century. He has worked closely with the Imperial War Museum to bring together two books in the Forgotten Voices series,...

, have been published. The Museum believes that historians have not taken full account of this material, and accordingly has made the full archive of recordings available to authors and researchers. Surviving veterans, returning home, often found that they could only discuss their experiences amongst themselves. Grouping together, they formed "veterans' associations" or "Legions".

Prisoners of war

About 8 million men surrendered and were held in POW camps during the war. All nations pledged to follow the Hague Conventions
Hague Conventions (1899 and 1907)
The Hague Conventions were two international treaties negotiated at international peace conferences at The Hague in the Netherlands: The First Hague Conference in 1899 and the Second Hague Conference in 1907...

 on fair treatment of prisoners of war. POWs' rate of survival was generally much higher than that of their peers at the front. Individual surrenders were uncommon; large units usually surrendered en masse. At the Battle of Tannenberg
Battle of Tannenberg (1914)
The Battle of Tannenberg was an engagement between the Russian Empire and the German Empire in the first days of World War I. It was fought by the Russian First and Second Armies against the German Eighth Army between 23 August and 30 August 1914. The battle resulted in the almost complete...

 92,000 Russians surrendered. When the besieged garrison of Kaunas
Kaunas
Kaunas is the second-largest city in Lithuania and has historically been a leading centre of Lithuanian economic, academic, and cultural life. Kaunas was the biggest city and the center of a powiat in Trakai Voivodeship of the Grand Duchy of Lithuania since 1413. During Russian Empire occupation...

 surrendered in 1915, some 20,000 Russians became prisoners. Over half of Russian losses (as a proportion of those captured, wounded, or killed) were to prisoner status; for Austria-Hungary 32%, for Italy 26%, for France 12%, for Germany 9%; for Britain 7%. Prisoners from the Allied armies totalled about 1.4 million (not including Russia, which lost 2.-3.5 million men as prisoners.) From the Central Powers about 3.3 million men became prisoners.

Germany held 2.5 million prisoners; Russia held 2.9 million; while Britain and France held about 720,000. Most were captured just prior to the Armistice. The U.S. held 48,000. The most dangerous moment was the act of surrender, when helpless soldiers were sometimes gunned down. Once prisoners reached a camp, conditions were, in general, satisfactory (and much better than in World War II), thanks in part to the efforts of the International Red Cross and inspections by neutral nations. However, conditions were terrible in Russia: starvation
Starvation
Starvation is a severe deficiency in caloric energy, nutrient and vitamin intake. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damage and eventually, death...

 was common for prisoners and civilians alike; about 15–20% of the prisoners in Russia died. In Germany, food was scarce, but only 5% died.

The Ottoman Empire often treated POWs poorly. Some 11,800 British Empire soldiers, most of them Indians, became prisoners after the Siege of Kut
Siege of Kut
The siege of Kut Al Amara , was the besieging of 8,000 strong British-Indian garrison in the town of Kut, 100 miles south of Baghdad, by the Ottoman Army. Its known also as 1st Battle of Kut. In 1915, its population was around 6,500...

 in Mesopotamia
Mesopotamia
Mesopotamia is a toponym for the area of the Tigris–Euphrates river system, largely corresponding to modern-day Iraq, northeastern Syria, southeastern Turkey and southwestern Iran.Widely considered to be the cradle of civilization, Bronze Age Mesopotamia included Sumer and the...

 in April 1916; 4,250 died in captivity.
Although many were in very bad condition when captured, Ottoman officers forced them to march 1100 kilometres (684 mi) to Anatolia
Anatolia
Anatolia is a geographic and historical term denoting the westernmost protrusion of Asia, comprising the majority of the Republic of Turkey...

. A survivor said: "We were driven along like beasts; to drop out was to die." The survivors were then forced to build a railway through the Taurus Mountains
Taurus Mountains
Taurus Mountains are a mountain complex in southern Turkey, dividing the Mediterranean coastal region of southern Turkey from the central Anatolian Plateau. The system extends along a curve from Lake Eğirdir in the west to the upper reaches of the Euphrates and Tigris rivers in the east...

.

In Russia, when the prisoners from the Czech Legion of the Austro-Hungarian army were released in 1917, they re-armed themselves and briefly became a military and diplomatic force during the Russian Civil War.

While the Allied prisoners of the Central Powers were quickly sent home at the end of active hostilities, the same treatment was not granted to Central Power prisoners of the Allies and Russia, many of whom served as forced labor, e.g., in France until 1920. They were released only after many approaches by the Red Cross to the Allied Supreme Council. German prisoners were still being held in Russia as late as 1924.

Military attachés and war correspondents

Military and civilian observers from every major power closely followed the course of the war. Many were able to report on events from a perspective somewhat akin to modern "embedded
Embedded journalist
Embedded journalism refers to news reporters being attached to military units involved in armed conflicts. While the term could be applied to many historical interactions between journalists and military personnel, it first came to be used in the media coverage of the 2003 invasion of Iraq...

" positions within the opposing land and naval forces. These military attachés and other observers prepared voluminous first-hand accounts of the war and analytical papers.

For example, former U.S. Army Captain Granville Fortescue
Granville Roland Fortescue
Granville Roland Fortescue was an American soldier, a Rough Rider serving with his cousin, Colonel Theodore Roosevelt in Cuba, a presidential aide in the first Roosevelt administration and later, a journalist and war correspondent for the London Standard during the Rif War in 1920 Spanish Morocco...

 followed the developments of the Gallipoli Campaign from an embedded perspective within the ranks of the Turkish defenders; and his report was passed through Turkish censors before being printed in London and New York. However, this observer's role was abandoned when the U.S. entered the war, as Fortescue immediately re-enlisted, sustaining wounds at Forest of Argonne
Forest of Argonne
The Forest of Argonne is a long strip of rocky mountain and wild woodland in north-eastern France.In 1792 Charles François Dumouriez outmaneuvered the invading forces of the Duke of Brunswick in the forest before the Battle of Valmy....

 in the Meuse-Argonne Offensive
Meuse-Argonne Offensive
The Meuse-Argonne Offensive, or Maas-Argonne Offensive, also called the Battle of the Argonne Forest, was a part of the final Allied offensive of World War I that stretched along the entire western front.-Overview:...

, September 1918.

In-depth observer narratives of the war and more narrowly focused professional journal articles were written soon after the war; and these post-war reports conclusively illustrated the battlefield destructiveness of this conflict. This was not the first time the tactics of entrenched positions for infantry defended with machine guns and artillery became vitally important. The Russo-Japanese War
Russo-Japanese War
The Russo-Japanese War was "the first great war of the 20th century." It grew out of rival imperial ambitions of the Russian Empire and Japanese Empire over Manchuria and Korea...

 had been closely observed by military attachés, war correspondents and other observers; but, from a 21st century perspective, it is now apparent that a range of tactical lessons were disregarded or not used in the preparations for war in Europe and throughout the Great War.

Support

In the Balkans, Yugoslav nationalists such as the leader Ante Trumbić
Ante Trumbic
Ante Trumbić was a Croatian politician in the early 20th century. He was one of the key politicians in the creation of a Yugoslav state....

 in the Balkans
Balkans
The Balkans is a geopolitical and cultural region of southeastern Europe...

 strongly supported the war, desiring the freedom of Yugoslavs
Yugoslavs
Yugoslavs is a national designation used by a minority of South Slavs across the countries of the former Yugoslavia and in the diaspora...

 from Austria-Hungary
Austria-Hungary
Austria-Hungary , more formally known as the Kingdoms and Lands Represented in the Imperial Council and the Lands of the Holy Hungarian Crown of Saint Stephen, was a constitutional monarchic union between the crowns of the Austrian Empire and the Kingdom of Hungary in...

 and other foreign powers and the creation of an independent Yugoslavia
Yugoslavia
Yugoslavia refers to three political entities that existed successively on the western part of the Balkans during most of the 20th century....

. The Yugoslav Committee
Yugoslav Committee
Yugoslav Committee was a political interest group formed by South Slavs from Austria-Hungary during World War I aimed at joining the existing south Slavic nations in an independent state.Founding members included:* Frano Supilo* Ante Trumbić...

 was formed in Paris on 30 April 1915 but shortly moved its office to London; Trumbić led the Committee.

In the Middle East, Arab nationalism
Arab nationalism
Arab nationalism is a nationalist ideology celebrating the glories of Arab civilization, the language and literature of the Arabs, calling for rejuvenation and political union in the Arab world...

 soared in Ottoman territories in response to the rise of Turkish nationalism during the war, with Arab nationalist leaders advocating the creation of a pan-Arab
Pan-Arabism
Pan-Arabism is an ideology espousing the unification--or, sometimes, close cooperation and solidarity against perceived enemies of the Arabs--of the countries of the Arab world, from the Atlantic Ocean to the Arabian Sea. It is closely connected to Arab nationalism, which asserts that the Arabs...

 state. In 1916, the Arab Revolt
Arab Revolt
The Arab Revolt was initiated by the Sherif Hussein bin Ali with the aim of securing independence from the ruling Ottoman Turks and creating a single unified Arab state spanning from Aleppo in Syria to Aden in Yemen.- Background :...

 began in Ottoman-controlled territories of the Middle East in an effort to achieve independence.

Italian nationalism
Italian nationalism
Italian nationalism refers to the nationalism of Italians or of Italian culture. It claims that Italians are the ethnic, cultural, and linguistic descendants of the ancient Romans who inhabited the Italian Peninsula for centuries. The origins of Italian nationalism have been traced to the...

 was stirred by the outbreak of the war and was initially strongly supported by a variety of political factions. One of the most prominent and popular Italian nationalist supporters of the war was Gabriele d'Annunzio
Gabriele D'Annunzio
Gabriele D'Annunzio or d'Annunzio was an Italian poet, journalist, novelist, and dramatist...

, who promoted Italian irredentism and helped sway the Italian public to support intervention in the war. The Italian Liberal Party
Italian Liberal Party
The Italian Liberal Party was a liberal political party in Italy.-Origins:The origins of liberalism in Italy came from the so-called "Historical Right", a parliamentary group formed by Camillo Benso di Cavour in the Parliament of the Kingdom of Sardinia following the 1848 revolution...

 under the leadership of Paolo Boselli
Paolo Boselli
Paolo Boselli was an Italian politician who served as the 34th Prime Minister of Italy during World War I.Boselli was born in Savona, Liguria....

 promoted intervention in the war on the side of the Allies and utilised the Dante Aligheri Society to promote Italian nationalism.

A number of socialist parties initially supported the war when it began in August 1914. But European socialists split on national lines, with the concept of class conflict
Class conflict
Class conflict is the tension or antagonism which exists in society due to competing socioeconomic interests between people of different classes....

 held by radical socialists such as Marxists and syndicalists
Syndicalism
Syndicalism is a type of economic system proposed as a replacement for capitalism and an alternative to state socialism, which uses federations of collectivised trade unions or industrial unions...

 being overborne by their patriotic support for war. Once the war began, Austrian, British, French, German, and Russian socialists followed the rising nationalist current by supporting their countries' intervention in the war.

Italian socialists were divided on whether to support the war or oppose it; some were militant supporters of the war, including Benito Mussolini
Benito Mussolini
Benito Amilcare Andrea Mussolini was an Italian politician who led the National Fascist Party and is credited with being one of the key figures in the creation of Fascism....

 and Leonida Bissolati
Leonida Bissolati
Leonida Bissolati was a leading exponent of the Italian socialist movement at the turn of the nineteenth century.- Biography :...

. However, the Italian Socialist Party
Italian Socialist Party
The Italian Socialist Party was a socialist and later social-democratic political party in Italy founded in Genoa in 1892.Once the dominant leftist party in Italy, it was eclipsed in status by the Italian Communist Party following World War II...

 decided to oppose the war after anti-militarist protestors were killed, resulting in a general strike
General strike
A general strike is a strike action by a critical mass of the labour force in a city, region, or country. While a general strike can be for political goals, economic goals, or both, it tends to gain its momentum from the ideological or class sympathies of the participants...

 called Red Week
Red Week
Red Week was the name given to a week of unrest which occurred in June, 1914. Over these seven days, Italy saw widespread rioting and large-scale strikes throughout the Italian provinces of Romagna and the Marche.-Origins of the 'Red Week':...

. The Italian Socialist Party purged itself of pro-war nationalist members, including Mussolini. Mussolini, a syndicalist
Syndicalism
Syndicalism is a type of economic system proposed as a replacement for capitalism and an alternative to state socialism, which uses federations of collectivised trade unions or industrial unions...

 who supported the war on grounds of irredentist claims on Italian-populated regions of Austria-Hungary, formed the pro-interventionist Il Popolo d'Italia
Il Popolo d'Italia
Il Popolo d'Italia , was an Italian newspaper founded by Benito Mussolini on November 15, 1914, as a result of his split with the Italian Socialist Party. Il Popolo d'Italia ran until July 24, 1943 and became the foundation for the Fascist movement in Italy after World War I...

and the Fasci Riviluzionario d'Azione Internazionalista ("Revolutionary Fasci for International Action") in October 1914 that later developed into the Fasci di Combattimento in 1919, the origin of fascism. Mussolini's nationalism enabled him to raise funds from Ansaldo (an armaments firm) and other companies to create Il Popolo d'Italia to convince socialists and revolutionaries to support the war.

In April 1918 the Rome Congress of Oppressed Nationalities met, including Czechoslovak, Italian, Polish
Poles
thumb|right|180px|The state flag of [[Poland]] as used by Polish government and diplomatic authoritiesThe Polish people, or Poles , are a nation indigenous to Poland. They are united by the Polish language, which belongs to the historical Lechitic subgroup of West Slavic languages of Central Europe...

, Transylvanian, and Yugoslav
Yugoslavia
Yugoslavia refers to three political entities that existed successively on the western part of the Balkans during most of the 20th century....

 representatives who urged the Allies to support national self-determination
Self-determination
Self-determination is the principle in international law that nations have the right to freely choose their sovereignty and international political status with no external compulsion or external interference...

 for the peoples residing within Austria-Hungary
Austria-Hungary
Austria-Hungary , more formally known as the Kingdoms and Lands Represented in the Imperial Council and the Lands of the Holy Hungarian Crown of Saint Stephen, was a constitutional monarchic union between the crowns of the Austrian Empire and the Kingdom of Hungary in...

.

Opposition

The trade union
Trade union
A trade union, trades union or labor union is an organization of workers that have banded together to achieve common goals such as better working conditions. The trade union, through its leadership, bargains with the employer on behalf of union members and negotiates labour contracts with...

 and socialist
Socialism
Socialism is an economic system characterized by social ownership of the means of production and cooperative management of the economy; or a political philosophy advocating such a system. "Social ownership" may refer to any one of, or a combination of, the following: cooperative enterprises,...

 movements had long voiced their opposition to a war, which they argued would mean only that workers would kill other workers in the interest of capitalism. Once war was declared, however, many socialists and trade unions backed their governments. Among the exceptions were the Bolshevik
Bolshevik
The Bolsheviks, originally also Bolshevists , derived from bol'shinstvo, "majority") were a faction of the Marxist Russian Social Democratic Labour Party which split apart from the Menshevik faction at the Second Party Congress in 1903....

s, the Socialist Party of America
Socialist Party of America
The Socialist Party of America was a multi-tendency democratic-socialist political party in the United States, formed in 1901 by a merger between the three-year-old Social Democratic Party of America and disaffected elements of the Socialist Labor Party which had split from the main organization...

, and the Italian Socialist Party
Italian Socialist Party
The Italian Socialist Party was a socialist and later social-democratic political party in Italy founded in Genoa in 1892.Once the dominant leftist party in Italy, it was eclipsed in status by the Italian Communist Party following World War II...

, and individuals such as Karl Liebknecht
Karl Liebknecht
was a German socialist and a co-founder with Rosa Luxemburg of the Spartacist League and the Communist Party of Germany. He is best known for his opposition to World War I in the Reichstag and his role in the Spartacist uprising of 1919...

, Rosa Luxemburg
Rosa Luxemburg
Rosa Luxemburg was a Marxist theorist, philosopher, economist and activist of Polish Jewish descent who became a naturalized German citizen...

, and their followers in Germany. There were also small anti-war groups in Britain and France.

Pope Benedict XV
Pope Benedict XV
Pope Benedict XV , born Giacomo Paolo Giovanni Battista della Chiesa, reigned as Pope from 3 September 1914 to 22 January 1922...

, elected to the papacy less than three months into World War I, made the war and its consequences the main focus of his early pontificate. In stark contrast to his predecesor
Pope Pius X
Pope Saint Pius X , born Giuseppe Melchiorre Sarto, was the 257th Pope of the Catholic Church, serving from 1903 to 1914. He was the first pope since Pope Pius V to be canonized. Pius X rejected modernist interpretations of Catholic doctrine, promoting traditional devotional practices and orthodox...

, five days after his election he spoke of his determination to do what he could to bring peace. His first encyclical, Ad Beatissimi Apostolorum
Ad Beatissimi Apostolorum
Ad Beatissimi Apostolorum is a encyclical of Pope Benedict XV given at St. Peter's, Rome, on the Feast of All Saints on November 1, 1914, in the first year of his Pontificate...

, given 1 November, 1914, was concerned with this subject. Seen as being biased in favour of the other and resented for weakening national morale, Benedict XV found his abilities and unique position as a religious emissary of peace ignored by the belligerent powers.

The 1915 Treaty of London between Italy and the Triple Entente included secret provisions whereby the Allies agreed with Italy to ignore papal peace moves towards the Central Powers. Consequently, the publication of Benedict's proposed seven-point Peace Note of August 1917 was roundly ignored by all parties except Austria-Hungary.

In Britain
United Kingdom of Great Britain and Ireland
The United Kingdom of Great Britain and Ireland was the formal name of the United Kingdom during the period when what is now the Republic of Ireland formed a part of it....

, in 1914, the Public Schools
Public Schools Act 1868
The Public Schools Act 1868 was enacted by the British Parliament to reform and regulate nine of the leading English boys' schools. They were described as "public schools" as admission was open to boys from anywhere and was not limited to those living in a particular locality...

 Officers' Training Corps annual camp was held at Tidworth Pennings, near Salisbury Plain
Salisbury Plain
Salisbury Plain is a chalk plateau in central southern England covering . It is part of the Southern England Chalk Formation and largely lies within the county of Wiltshire, with a little in Hampshire. The plain is famous for its rich archaeology, including Stonehenge, one of England's best known...

. Head of the British Army
British Army
The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...

 Lord Kitchener was to review the cadet
Cadet
A cadet is a trainee to become an officer in the military, often a person who is a junior trainee. The term comes from the term "cadet" for younger sons of a noble family.- Military context :...

s, but the imminence of the war prevented him. General Horace Smith-Dorrien
Horace Smith-Dorrien
General Sir Horace Lockwood Smith-Dorrien GCB, GCMG, DSO, ADC was a British soldier and commander of the British II Corps and Second Army of the BEF during World War I.-Early life and career:...

 was sent instead. He surprised the two-or-three thousand cadets by declaring (in the words of Donald Christopher Smith, a Bermudian
Bermuda
Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...

 cadet who was present), that war should be avoided at almost any cost, that war would solve nothing, that the whole of Europe and more besides would be reduced to ruin, and that the loss of life would be so large that whole populations would be decimated. In our ignorance I, and many of us, felt almost ashamed of a British General who uttered such depressing and unpatriotic sentiments, but during the next four years, those of us who survived the holocaust-probably not more than one-quarter of us - learned how right the General's prognosis was and how courageous he had been to utter it. Voicing these sentiments did not hinder Smith-Dorien's career, or prevent him from doing his duty in World War I to the best of his abilities.

E. D. Morel
E. D. Morel
Edmund Dene Morel, originally Georges Eduard Pierre Achille Morel de Ville was a British journalist, author and socialist politician. In collaboration with Roger Casement, the Congo Reform Association and others, Morel, in newspapers such as his West African Mail, led a campaign against slavery...

  had been extremely suspicious of the secret diplomacy pursued by the British Foreign Office, and in 1911 he showed how a secret understanding between Britain and France over the control of Morocco, followed by a campaign in the British press based on misleading Foreign Office briefings, had stitched up Germany and very nearly caused a European war. In February 1912, he warned that "no greater disaster could befall both peoples [Britain and Germany], and all that is most worthy of preservation in modern civilization, than a war between them". Convinced that Britain had struck a second secret agreement with France that would drag the nation into any war which involved Russia, he campaigned for such treaties to be made public; for recognition that Germany had been hoodwinked over Morocco; and for the British government to seek to broker a reconciliation between France and Germany. In response, British ministers lied. The prime minister and the foreign secretary repeatedly denied that there was any secret agreement with France. Only on the day war was declared did the foreign secretary admit that a treaty had been in place since 1906. It ensured that Britain would have to fight from the moment Russia mobilised. Morel continued to oppose the war, was reviled in the press and physically attacked seven times for it, and eventually was imprisoned in 1917.

At the end of July, 1914, when it became clear to the British government that the country was on the verge of war with Germany, four senior members of the government, David Lloyd George
David Lloyd George
David Lloyd George, 1st Earl Lloyd-George of Dwyfor OM, PC was a British Liberal politician and statesman...

 (Chancellor of the Exchequer), Sir Charles Trevelyan
Sir Charles Trevelyan, 3rd Baronet
Sir Charles Philips Trevelyan, 3rd Baronet PC , the Lord Lieutenant of Northumberland, was a British Liberal, and later Labour, politician and landowner...

 (Parliamentary Secretary of the Board of Education), John Burns
John Burns
John Elliot Burns was an English trade unionist and politician of the late 19th and early 20th centuries, particularly associated with London politics. He was a socialist and then a Liberal Member of Parliament and Minister. He was anti-alcohol and a keen sportsman...

 (President of the Local Government Board), and John Morley (Secretary of State for India), were opposed to the country becoming involved in a European war. They informed the Prime Minister, Herbert Asquith, that they intended to resign over the issue. When war was declared on 4 August, three of the men, Trevelyan, Burns, and Morley, resigned, but Asquith managed to persuade Lloyd George, his Chancellor of the Exchequer, to change his mind.
The day after war was declared, Trevelyan began contacting friends about a new political organisation he intended to form to oppose the war. This included two pacifist members of the Liberal Party, Norman Angell
Norman Angell
Sir Ralph Norman Angell was an English lecturer, journalist, author, and Member of Parliament for the Labour Party.Angell was one of the principal founders of the Union of Democratic Control...

 and E. D. Morel, and Ramsay MacDonald
Ramsay MacDonald
James Ramsay MacDonald, PC, FRS was a British politician who was the first ever Labour Prime Minister, leading a minority government for two terms....

, the leader of the Labour Party. A meeting was held, and after considering names such as the Peoples' Emancipation Committee and the Peoples' Freedom League, they selected the Union of Democratic Control
Union of Democratic Control
The Union of Democratic Control was a British pressure group formed in 1914 to press for a more responsive foreign policy. While not a pacifist organization, it was opposed to military influence in government.-World War I:...

.
The four men agreed that one of the main reasons for the conflict was the secret diplomacy of people like Britain's foreign secretary, Sir Edward Grey.
The founders of the Union of Democratic Control
Union of Democratic Control
The Union of Democratic Control was a British pressure group formed in 1914 to press for a more responsive foreign policy. While not a pacifist organization, it was opposed to military influence in government.-World War I:...

 produced a manifesto and invited people to support it. Over the next few weeks several leading figures joined the organisation. This included J. A. Hobson, Charles Buxton, Ottoline Morrell, Philip Morrell, Frederick Pethick-Lawrence, Arnold Rowntree, Morgan Philips Price, George Cadbury, Helena Swanwick, Fred Jowett, Tom Johnston, Bertrand Russell, Philip Snowden, Ethel Snowden, David Kirkwood, William Anderson, Mary Sheepshanks, Isabella Ford, H. H. Brailsford, Israel Zangwill, Margaret Llewelyn Davies, Konni Zilliacus, Margaret Sackville and Olive Schreiner.
Ramsay MacDonald came under attack from newspapers because of his opposition to the First World War. On 1 October 1914, The Times published a leading article entitled "Helping the Enemy", in which it wrote that "no paid agent of Germany had served her better" than MacDonald had done. The newspaper also included an article by Ignatius Valentine Chirol, who argued: "We may be rightly proud of the tolerance we display towards even the most extreme licence of speech in ordinary times....Mr. MacDonald's case is a very different one. In time of actual war...Mr. MacDonald has sought to besmirch the reputation of his country by openly charging with disgraceful duplicity the Ministers who are its chosen representatives, and he has helped the enemy State....Such action oversteps the bounds of even the most excessive toleration, and cannot be properly or safely disregarded by the British Government or the British people."

Many countries jailed those who spoke out against the conflict. These included Eugene Debs in the United States and Bertrand Russell
Bertrand Russell
Bertrand Arthur William Russell, 3rd Earl Russell, OM, FRS was a British philosopher, logician, mathematician, historian, and social critic. At various points in his life he considered himself a liberal, a socialist, and a pacifist, but he also admitted that he had never been any of these things...

 in Britain. In the U.S., the Espionage Act of 1917
Espionage Act of 1917
The Espionage Act of 1917 is a United States federal law passed on June 15, 1917, shortly after the U.S. entry into World War I. It has been amended numerous times over the years. It was originally found in Title 50 of the U.S. Code but is now found under Title 18, Crime...

 and Sedition Act of 1918
Sedition Act of 1918
The Sedition Act of 1918 was an Act of the United States Congress that extended the Espionage Act of 1917 to cover a broader range of offenses, notably speech and the expression of opinion that cast the government or the war effort in a negative light or interfered with the sale of government bonds...

 made it a federal crime to oppose military recruitment or make any statements deemed "disloyal". Publications at all critical of the government were removed from circulation by postal censors, and many served long prison sentences for statements of fact deemed unpatriotic.

A number of nationalists opposed intervention, particularly within states that the nationalists were hostile to. Irish nationalists
Irish nationalism
Irish nationalism manifests itself in political and social movements and in sentiment inspired by a love for Irish culture, language and history, and as a sense of pride in Ireland and in the Irish people...

 staunchly opposed taking part in the intervention of the United Kingdom of Great Britain and Ireland
United Kingdom of Great Britain and Ireland
The United Kingdom of Great Britain and Ireland was the formal name of the United Kingdom during the period when what is now the Republic of Ireland formed a part of it....

. The war began amid the Home Rule crisis in Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 that had begun in 1912, and by 1914 there was a serious possibility of an outbreak of civil war
Civil war
A civil war is a war between organized groups within the same nation state or republic, or, less commonly, between two countries created from a formerly-united nation state....

 in Ireland between Irish unionists and republicans. Irish nationalists and Marxists attempted to pursue Irish independence, culminating in the Easter Rising
Easter Rising
The Easter Rising was an insurrection staged in Ireland during Easter Week, 1916. The Rising was mounted by Irish republicans with the aims of ending British rule in Ireland and establishing the Irish Republic at a time when the British Empire was heavily engaged in the First World War...

 of 1916, with Germany sending 20,000 rifles to Ireland in order to stir unrest in the United Kingdom. The UK government placed Ireland under martial law
Martial law
Martial law is the imposition of military rule by military authorities over designated regions on an emergency basis— only temporary—when the civilian government or civilian authorities fail to function effectively , when there are extensive riots and protests, or when the disobedience of the law...

 in response to the Easter Rising.

Other opposition came from conscientious objector
Conscientious objector
A conscientious objector is an "individual who has claimed the right to refuse to perform military service" on the grounds of freedom of thought, conscience, and/or religion....

s – some socialist, some religious – who refused to fight. In Britain 16,000 people asked for conscientious objector status. Many suffered years of prison, including solitary confinement
Solitary confinement
Solitary confinement is a special form of imprisonment in which a prisoner is isolated from any human contact, though often with the exception of members of prison staff. It is sometimes employed as a form of punishment beyond incarceration for a prisoner, and has been cited as an additional...

 and bread and water diets. Even after the war, in Britain many job advertisements were marked "No conscientious objectors need apply".

The Central Asian Revolt started in the summer of 1916, when the Russian Empire
Russian Empire
The Russian Empire was a state that existed from 1721 until the Russian Revolution of 1917. It was the successor to the Tsardom of Russia and the predecessor of the Soviet Union...

 government ended its exemption of Muslims from military service.

In 1917, a series of mutinies in the French army
French Army Mutinies (1917)
The French Army Mutinies of 1917 took place amongst the French troops on the Western Front in Northern France. They started just after the conclusion of the disastrous Second Battle of the Aisne, the main action in the Nivelle Offensive, and involved, to various degrees, nearly half of the French...

 led to dozens of soldiers being executed and many more imprisoned.

In Milan
Milan
Milan is the second-largest city in Italy and the capital city of the region of Lombardy and of the province of Milan. The city proper has a population of about 1.3 million, while its urban area, roughly coinciding with its administrative province and the bordering Province of Monza and Brianza ,...

 in May 1917, Bolshevik
Bolshevik
The Bolsheviks, originally also Bolshevists , derived from bol'shinstvo, "majority") were a faction of the Marxist Russian Social Democratic Labour Party which split apart from the Menshevik faction at the Second Party Congress in 1903....

 revolutionaries organised and engaged in rioting calling for an end to the war, and managed to close down factories and stop public transportation. The Italian army was forced to enter Milan
Milan
Milan is the second-largest city in Italy and the capital city of the region of Lombardy and of the province of Milan. The city proper has a population of about 1.3 million, while its urban area, roughly coinciding with its administrative province and the bordering Province of Monza and Brianza ,...

 with tanks and machine guns to face Bolsheviks and anarchists
Anarchism
Anarchism is generally defined as the political philosophy which holds the state to be undesirable, unnecessary, and harmful, or alternatively as opposing authority in the conduct of human relations...

, who fought violently until May 23 when the army gained control of the city. Almost fifty people (including three Italian soldiers) were killed and over 800 people arrested.

The Conscription Crisis of 1917
Conscription Crisis of 1917
The Conscription Crisis of 1917 was a political and military crisis in Canada during World War I.-Background:...

 in Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 erupted when conservative Prime Minister Robert Borden
Robert Borden
Sir Robert Laird Borden, PC, GCMG, KC was a Canadian lawyer and politician. He served as the eighth Prime Minister of Canada from October 10, 1911 to July 10, 1920, and was the third Nova Scotian to hold this office...

 brought in compulsory military service over the objection of French-speaking Quebec
Quebec
Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....

ers. Out of approximately 625,000 Canadians who served, about 60,000 were killed and another 173,000 wounded.

In 1917, Emperor Charles I of Austria secretly entered into peace negotiations with the Allied powers, with his brother-in-law Sixtus
Prince Sixtus of Bourbon-Parma
Prince Sixtus of Bourbon-Parma was a Prince of the Duchy of Parma, a Belgian officer in the First World War, and the central figure in the Sixtus Affair.- Biography :Sixtus was a son of the last Duke of Parma, Robert I and his...

 as intermediary, without the knowledge of his ally Germany. He failed, however, because of the resistance of Italy.

In September 1917, Russian soldiers in France
Russian Expeditionary Force in France
The Russian Expeditionary Force was a World War I military force sent to France by the Russian Empire. In 1915 the French requested that Russian troops be sent to fight alongside their own army on the Western Front. Initially they asked for 300,000 men, an absurdly high figure, probably based on...

 began questioning why they were fighting for the French at all and mutinied. In Russia, opposition to the war led to soldiers also establishing their own revolutionary committees, which helped foment the October Revolution
October Revolution
The October Revolution , also known as the Great October Socialist Revolution , Red October, the October Uprising or the Bolshevik Revolution, was a political revolution and a part of the Russian Revolution of 1917...

 of 1917, with the call going up for "bread, land, and peace". The Bolsheviks agreed to a peace treaty with Germany, the peace of Brest-Litovsk
Treaty of Brest-Litovsk
The Treaty of Brest-Litovsk was a peace treaty signed on March 3, 1918, mediated by South African Andrik Fuller, at Brest-Litovsk between Russia and the Central Powers, headed by Germany, marking Russia's exit from World War I.While the treaty was practically obsolete before the end of the year,...

, despite its harsh conditions.

In northern Germany
German Empire
The German Empire refers to Germany during the "Second Reich" period from the unification of Germany and proclamation of Wilhelm I as German Emperor on 18 January 1871, to 1918, when it became a federal republic after defeat in World War I and the abdication of the Emperor, Wilhelm II.The German...

, the end of October 1918, saw the beginning of the German Revolution of 1918–1919. Units of the German Navy refused to set sail for a last, large-scale operation in a war which they saw as good as lost; this initiated the uprising. The sailors' revolt
Wilhelmshaven mutiny
The Kiel mutiny was a major revolt by sailors of the German High Seas Fleet on 3 November 1918. The revolt triggered the German revolution which was to sweep aside the monarchy within a few days. It ultimately led to the end of the First World War and to the establishment of the Weimar Republic.-...

 which then ensued in the naval ports of Wilhelmshaven
Wilhelmshaven
Wilhelmshaven is a coastal town in Lower Saxony, Germany. It is situated on the western side of the Jade Bight, a bay of the North Sea.-History:...

 and Kiel
Kiel
Kiel is the capital and most populous city in the northern German state of Schleswig-Holstein, with a population of 238,049 .Kiel is approximately north of Hamburg. Due to its geographic location in the north of Germany, the southeast of the Jutland peninsula, and the southwestern shore of the...

 spread across the whole country within days and led to the proclamation of a republic on 9 November 1918 and shortly thereafter to the abdication of Kaiser Wilhelm II.

Conscription

As the war slowly turned into a war of attrition
Attrition warfare
Attrition warfare is a military strategy in which a belligerent side attempts to win a war by wearing down its enemy to the point of collapse through continuous losses in personnel and matériel....

, conscription
Conscription
Conscription is the compulsory enlistment of people in some sort of national service, most often military service. Conscription dates back to antiquity and continues in some countries to the present day under various names...

 was implemented in some countries. This issue was particularly explosive in Canada and Australia. In the former it opened a political gap between French-Canadians, who claimed their true loyalty was to Canada and not the British Empire, and members of the Anglophone majority, who saw the war as a duty to both Britain and Canada. Prime Minister Robert Borden
Robert Borden
Sir Robert Laird Borden, PC, GCMG, KC was a Canadian lawyer and politician. He served as the eighth Prime Minister of Canada from October 10, 1911 to July 10, 1920, and was the third Nova Scotian to hold this office...

 pushed through a Military Service Act
Military Service Act (Canada)
In Canadian history, the Military Service Act was a 1917 Act passed by the Canadian government to effort needed more soldiers, so on April 20, 1918, an order-in-council was passed that removed exemptions from the Military Service Act. This left farming operations across Canada short of much-needed...

, provoking the Conscription Crisis of 1917
Conscription Crisis of 1917
The Conscription Crisis of 1917 was a political and military crisis in Canada during World War I.-Background:...

. In Australia, a sustained pro-conscription campaign by Prime Minister Billy Hughes
Billy Hughes
William Morris "Billy" Hughes, CH, KC, MHR , Australian politician, was the seventh Prime Minister of Australia from 1915 to 1923....

 caused a split in the Australian Labor Party
Australian Labor Party
The Australian Labor Party is an Australian political party. It has been the governing party of the Commonwealth of Australia since the 2007 federal election. Julia Gillard is the party's federal parliamentary leader and Prime Minister of Australia...

, so Hughes formed the Nationalist Party of Australia
Nationalist Party of Australia
The Nationalist Party of Australia was an Australian political party. It was formed on 17 February 1917 from a merger between the conservative Commonwealth Liberal Party and the National Labor Party, the name given to the pro-conscription defectors from the Australian Labor Party led by Prime...

 in 1917 to pursue the matter. Nevertheless, the labour movement
Labour movement
The term labour movement or labor movement is a broad term for the development of a collective organization of working people, to campaign in their own interest for better treatment from their employers and governments, in particular through the implementation of specific laws governing labour...

, the Catholic Church, and Irish nationalist expatriates successfully opposed Hughes' push, which was rejected in two plebiscites
Australian plebiscite, 1917
The 1917 Australian plebiscite was held on 20 December 1917. It contained one question.* Are you in favour of the proposal of the Commonwealth Government for reinforcing the Australian Imperial Force overseas?-The Plebiscite:...

.

Conscription put into uniform nearly every physically fit man in Britain, six of ten million eligible. Of these, about 750,000 lost their lives and 1,700,000 were wounded. Most deaths were to young unmarried men; however, 160,000 wives lost husbands and 300,000 children lost fathers.

Health and economic effects

No other war had changed the map of Europe so dramatically. Four empires disappeared: the German, Austro-Hungarian, Ottoman, and Russian. Four dynasties, together with their ancillary aristocracies, all fell after the war: the Hohenzollerns
House of Hohenzollern
The House of Hohenzollern is a noble family and royal dynasty of electors, kings and emperors of Prussia, Germany and Romania. It originated in the area around the town of Hechingen in Swabia during the 11th century. They took their name from their ancestral home, the Burg Hohenzollern castle near...

, the Habsburg
Habsburg
The House of Habsburg , also found as Hapsburg, and also known as House of Austria is one of the most important royal houses of Europe and is best known for being an origin of all of the formally elected Holy Roman Emperors between 1438 and 1740, as well as rulers of the Austrian Empire and...

s, the Romanov
Romanov
The House of Romanov was the second and last imperial dynasty to rule over Russia, reigning from 1613 until the February Revolution abolished the crown in 1917...

s, and the Ottomans
Ottoman Dynasty
The Ottoman Dynasty ruled the Ottoman Empire from 1299 to 1922, beginning with Osman I , though the dynasty was not proclaimed until Orhan Bey declared himself sultan...

. Belgium and Serbia were badly damaged, as was France, with 1.4 million soldiers dead, not counting other casualties. Germany and Russia were similarly affected.

The war had profound economic consequences. Of the 60 million European soldiers who were mobilised from 1914 to 1918, 8 million were killed, 7 million were permanently disabled, and 15 million were seriously injured. Germany lost 15.1% of its active male population, Austria–Hungary lost 17.1%, and France lost 10.5%. About 750,000 German civilians died from starvation
Starvation
Starvation is a severe deficiency in caloric energy, nutrient and vitamin intake. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damage and eventually, death...

 caused by the British blockade during the war. By the end of the war, famine had killed approximately 100,000 people in Lebanon. The best estimates of the death toll from the Russian famine of 1921
Russian famine of 1921
The Russian famine of 1921, also known as Povolzhye famine, which began in the early spring of that year, and lasted through 1922, was a severe famine that occurred in Bolshevik Russia...

 run from 5 million to 10 million people. By 1922, there were between 4.5 million and 7 million homeless children in Russia as a result of nearly a decade of devastation from World War I, the Russian Civil War, and the subsequent famine of 1920–1922. Numerous anti-Soviet Russians fled the country after the Revolution; by the 1930s the northern Chinese city of Harbin
Harbin
Harbin ; Manchu language: , Harbin; Russian: Харби́н Kharbin ), is the capital and largest city of Heilongjiang Province in Northeast China, lying on the southern bank of the Songhua River...

 had 100,000 Russians. Thousands more emigrated to France, England, and the United States.

Diseases flourished in the chaotic wartime conditions. In 1914 alone, louse-borne epidemic typhus killed 200,000 in Serbia. From 1918 to 1922, Russia had about 25 million infections and 3 million deaths from epidemic typhus. Whereas before World War I Russia had about 3.5 million cases of malaria
Malaria
Malaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...

, its people suffered more than 13 million cases in 1923. In addition, a major influenza epidemic spread around the world. Overall, the 1918 flu pandemic killed at least 50 million people.

Lobbying by Chaim Weizmann
Chaim Weizmann
Chaim Azriel Weizmann, , was a Zionist leader, President of the Zionist Organization, and the first President of the State of Israel. He was elected on 1 February 1949, and served until his death in 1952....

 and fear that American Jews would encourage the USA to support Germany culminated in the British government's Balfour Declaration of 1917, endorsing creation of a Jewish homeland in Palestine
Palestine
Palestine is a conventional name, among others, used to describe the geographic region between the Mediterranean Sea and the Jordan River, and various adjoining lands....

. A total of more than 1,172,000 Jewish soldiers served in the Allied and Central Power forces in World War I, including 275,000 in Austria-Hungary and 450,000 in Czarist Russia.

The social disruption and widespread violence of the Revolution of 1917 and the ensuing Russian Civil War
Russian Civil War
The Russian Civil War was a multi-party war that occurred within the former Russian Empire after the Russian provisional government collapsed to the Soviets, under the domination of the Bolshevik party. Soviet forces first assumed power in Petrograd The Russian Civil War (1917–1923) was a...

 sparked more than 2,000 pogrom
Pogrom
A pogrom is a form of violent riot, a mob attack directed against a minority group, and characterized by killings and destruction of their homes and properties, businesses, and religious centres...

s in the former Russian Empire, mostly in the Ukraine
Ukraine after the Russian Revolution
Ukrainian territory was fought over by various factions after the Russian Revolution of 1917 and the First World War, which added the collapse of Austria-Hungary to that of the Imperial Russia. The crumbling of the empires had a great effect on the Ukrainian nationalist movement and in the short...

. An estimated 60,000–200,000 civilian Jews were killed in the atrocities.

In the aftermath of World War I, Greece fought
Greco-Turkish War (1919-1922)
The Greco–Turkish War of 1919–1922, known as the Western Front of the Turkish War of Independence in Turkey and the Asia Minor Campaign or the Asia Minor Catastrophe in Greece, was a series of military events occurring during the partitioning of the Ottoman Empire after World War I between May...

 against Turkish nationalists led by Mustafa Kemal
Mustafa Kemal Atatürk
Mustafa Kemal Atatürk was an Ottoman and Turkish army officer, revolutionary statesman, writer, and the first President of Turkey. He is credited with being the founder of the Republic of Turkey....

, a war which resulted in a massive population exchange between the two countries
Population exchange between Greece and Turkey
The 1923 population exchange between Greece and Turkey was based upon religious identity, and involved the Greek Orthodox citizens of Turkey and the Muslim citizens of Greece...

 under the Treaty of Lausanne
Treaty of Lausanne
The Treaty of Lausanne was a peace treaty signed in Lausanne, Switzerland on 24 July 1923, that settled the Anatolian and East Thracian parts of the partitioning of the Ottoman Empire. The treaty of Lausanne was ratified by the Greek government on 11 February 1924, by the Turkish government on 31...

. According to various sources, several hundred thousand Pontic Greeks
Pontic Greeks
The Pontians are an ethnic group traditionally living in the Pontus region, the shores of Turkey's Black Sea...

 died during this period.

Peace treaties and national boundaries

After the war, the Paris Peace Conference
Paris Peace Conference, 1919
The Paris Peace Conference was the meeting of the Allied victors following the end of World War I to set the peace terms for the defeated Central Powers following the armistices of 1918. It took place in Paris in 1919 and involved diplomats from more than 32 countries and nationalities...

 imposed a series of peace treaties on the Central Powers. The 1919 Treaty of Versailles
Treaty of Versailles
The Treaty of Versailles was one of the peace treaties at the end of World War I. It ended the state of war between Germany and the Allied Powers. It was signed on 28 June 1919, exactly five years after the assassination of Archduke Franz Ferdinand. The other Central Powers on the German side of...

 officially ended the war. Building on Wilson's 14th point
Fourteen Points
The Fourteen Points was a speech given by United States President Woodrow Wilson to a joint session of Congress on January 8, 1918. The address was intended to assure the country that the Great War was being fought for a moral cause and for postwar peace in Europe...

, the Treaty of Versailles also brought into being the League of Nations
League of Nations
The League of Nations was an intergovernmental organization founded as a result of the Paris Peace Conference that ended the First World War. It was the first permanent international organization whose principal mission was to maintain world peace...

 on 28 June 1919.

In signing the treaty, Germany acknowledged responsibility for the war, and agreed to pay enormous war reparations
War reparations
War reparations are payments intended to cover damage or injury during a war. Generally, the term war reparations refers to money or goods changing hands, rather than such property transfers as the annexation of land.- History :...

 and award territory to the victors. The "Guilt Thesis" became a controversial explanation of later events among analysts in Britain and the United States. The Treaty of Versailles caused enormous bitterness in Germany, which nationalist movements, especially the Nazis, exploited with a conspiracy theory
Conspiracy theory
A conspiracy theory explains an event as being the result of an alleged plot by a covert group or organization or, more broadly, the idea that important political, social or economic events are the products of secret plots that are largely unknown to the general public.-Usage:The term "conspiracy...

 they called the Dolchstosslegende (Stab-in-the-back legend). The Weimar Republic
Weimar Republic
The Weimar Republic is the name given by historians to the parliamentary republic established in 1919 in Germany to replace the imperial form of government...

 lost the former colonial possessions
German colonial empire
The German colonial empire was an overseas domain formed in the late 19th century as part of the German Empire. Short-lived colonial efforts by individual German states had occurred in preceding centuries, but Imperial Germany's colonial efforts began in 1884...

 and was saddled with accepting blame for the war, as well as paying punitive reparations
World War I reparations
World War I reparations refers to the payments and transfers of property and equipment that Germany was forced to make under the Treaty of Versailles following its defeat during World War I...

 for it. Unable to pay them with exports (as a result of territorial losses and postwar recession), Germany did so by borrowing from the United States. Runaway inflation in the 1920s contributed to the economic collapse of the Weimar Republic
Weimar Republic
The Weimar Republic is the name given by historians to the parliamentary republic established in 1919 in Germany to replace the imperial form of government...

, and the payment of reparations was suspended in 1931 following the Stock Market Crash
Stock market crash
A stock market crash is a sudden dramatic decline of stock prices across a significant cross-section of a stock market, resulting in a significant loss of paper wealth. Crashes are driven by panic as much as by underlying economic factors...

 of 1929 and the beginnings of the Great Depression
Great Depression
The Great Depression was a severe worldwide economic depression in the decade preceding World War II. The timing of the Great Depression varied across nations, but in most countries it started in about 1929 and lasted until the late 1930s or early 1940s...

 worldwide.
Austria–Hungary was partitioned into several successor states, including Austria, Hungary, Czechoslovakia
Czechoslovakia
Czechoslovakia or Czecho-Slovakia was a sovereign state in Central Europe which existed from October 1918, when it declared its independence from the Austro-Hungarian Empire, until 1992...

, and Yugoslavia
Yugoslavia
Yugoslavia refers to three political entities that existed successively on the western part of the Balkans during most of the 20th century....

, largely but not entirely along ethnic lines. Transylvania
Transylvania
Transylvania is a historical region in the central part of Romania. Bounded on the east and south by the Carpathian mountain range, historical Transylvania extended in the west to the Apuseni Mountains; however, the term sometimes encompasses not only Transylvania proper, but also the historical...

 was shifted from Hungary
Hungary
Hungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...

 to Greater Romania
Greater Romania
The Greater Romania generally refers to the territory of Romania in the years between the First World War and the Second World War, the largest geographical extent of Romania up to that time and its largest peacetime extent ever ; more precisely, it refers to the territory of the Kingdom of...

. The details were contained in the Treaty of Saint-Germain
Treaty of Saint-Germain
The Treaty of Saint-Germain-en-Laye, was signed on 10 September 1919 by the victorious Allies of World War I on the one hand and by the new Republic of Austria on the other...

 and the Treaty of Trianon
Treaty of Trianon
The Treaty of Trianon was the peace agreement signed in 1920, at the end of World War I, between the Allies of World War I and Hungary . The treaty greatly redefined and reduced Hungary's borders. From its borders before World War I, it lost 72% of its territory, which was reduced from to...

. As a result of the Treaty of Trianon
Treaty of Trianon
The Treaty of Trianon was the peace agreement signed in 1920, at the end of World War I, between the Allies of World War I and Hungary . The treaty greatly redefined and reduced Hungary's borders. From its borders before World War I, it lost 72% of its territory, which was reduced from to...

, 3.3 million Hungarians came under foreign rule. Although the Hungarians made up 54% of the population of the pre-war Kingdom of Hungary
Kingdom of Hungary
The Kingdom of Hungary comprised present-day Hungary, Slovakia and Croatia , Transylvania , Carpatho Ruthenia , Vojvodina , Burgenland , and other smaller territories surrounding present-day Hungary's borders...

, only 32% of its territory was left to Hungary. Between 1920 and 1924, 354,000 Hungarians fled former Hungarian territories attached to Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

, Czechoslovakia
Czechoslovakia
Czechoslovakia or Czecho-Slovakia was a sovereign state in Central Europe which existed from October 1918, when it declared its independence from the Austro-Hungarian Empire, until 1992...

, and Yugoslavia
Yugoslavia
Yugoslavia refers to three political entities that existed successively on the western part of the Balkans during most of the 20th century....

.

The Russian Empire, which had withdrawn from the war in 1917 after the October Revolution
October Revolution
The October Revolution , also known as the Great October Socialist Revolution , Red October, the October Uprising or the Bolshevik Revolution, was a political revolution and a part of the Russian Revolution of 1917...

, lost much of its western frontier as the newly independent nations of Estonia
Estonia
Estonia , officially the Republic of Estonia , is a state in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by Lake Peipsi and the Russian Federation . Across the Baltic Sea lies...

, Finland, Latvia
Latvia
Latvia , officially the Republic of Latvia , is a country in the Baltic region of Northern Europe. It is bordered to the north by Estonia , to the south by Lithuania , to the east by the Russian Federation , to the southeast by Belarus and shares maritime borders to the west with Sweden...

, Lithuania
Lithuania
Lithuania , officially the Republic of Lithuania is a country in Northern Europe, the biggest of the three Baltic states. It is situated along the southeastern shore of the Baltic Sea, whereby to the west lie Sweden and Denmark...

, and Poland
Second Polish Republic
The Second Polish Republic, Second Commonwealth of Poland or interwar Poland refers to Poland between the two world wars; a period in Polish history in which Poland was restored as an independent state. Officially known as the Republic of Poland or the Commonwealth of Poland , the Polish state was...

 were carved from it. Bessarabia
Bessarabia
Bessarabia is a historical term for the geographic region in Eastern Europe bounded by the Dniester River on the east and the Prut River on the west....

 was re-attached to Greater Romania
Greater Romania
The Greater Romania generally refers to the territory of Romania in the years between the First World War and the Second World War, the largest geographical extent of Romania up to that time and its largest peacetime extent ever ; more precisely, it refers to the territory of the Kingdom of...

, as it had been a Romanian territory for more than a thousand years.

The Ottoman Empire disintegrated, and much of its non-Anatolia
Anatolia
Anatolia is a geographic and historical term denoting the westernmost protrusion of Asia, comprising the majority of the Republic of Turkey...

n territory was awarded to various Allied powers as protectorates. The Turkish core was reorganised as the Republic of Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...

. The Ottoman Empire was to be partitioned by the Treaty of Sèvres
Treaty of Sèvres
The Treaty of Sèvres was the peace treaty between the Ottoman Empire and Allies at the end of World War I. The Treaty of Versailles was signed with Germany before this treaty to annul the German concessions including the economic rights and enterprises. Also, France, Great Britain and Italy...

 of 1920. This treaty was never ratified by the Sultan and was rejected by the Turkish republican movement, leading to the Turkish Independence War and, ultimately, to the 1923 Treaty of Lausanne
Treaty of Lausanne
The Treaty of Lausanne was a peace treaty signed in Lausanne, Switzerland on 24 July 1923, that settled the Anatolian and East Thracian parts of the partitioning of the Ottoman Empire. The treaty of Lausanne was ratified by the Greek government on 11 February 1924, by the Turkish government on 31...

.

Legacy

..."Strange, friend," I said, "Here is no cause to mourn."
"None," said the other, "Save the undone years"...
Wilfred Owen
Wilfred Owen
Wilfred Edward Salter Owen MC was an English poet and soldier, one of the leading poets of the First World War...

, Strange Meeting, 1918


The first tentative efforts to comprehend the meaning and consequences of modern warfare began during the initial phases of the war, and this process continued throughout and after the end of hostilities.

Memorials

Memorials were erected in thousands of villages and towns. Close to battlefields, those buried in improvised burial grounds were gradually moved to formal graveyards under the care of organisations such as the Commonwealth War Graves Commission
Commonwealth War Graves Commission
The Commonwealth War Graves Commission is an intergovernmental organisation of six independent member states whose principal function is to mark, record and maintain the graves, and places of commemoration, of Commonwealth of Nations military service members who died in the two World Wars...

, the American Battle Monuments Commission
American Battle Monuments Commission
The American Battle Monuments Commission is a small independent agency of the United States government. Established by Congress in 1923, it is responsible for:...

, the German War Graves Commission
German War Graves Commission
The German War Graves Commission is responsible for the maintenance and upkeep of German war graves in Europe and North Africa...

, and Le Souvenir français
Le Souvenir français
Le Souvenir français is a French association for maintaining war memorials and war memory, comparable to the Commonwealth War Graves Commission....

. Many of these graveyards also have central monuments to the missing or unidentified dead, such as the Menin Gate
Menin Gate
The Menin Gate Memorial to the Missing is a war memorial in Ypres, Belgium dedicated to the commemoration of British and Commonwealth soldiers who were killed in the Ypres Salient of the First World War and whose graves are unknown...

 memorial and the Thiepval Memorial to the Missing of the Somme.

On 3 May 1915, during the Second Battle of Ypres
Second Battle of Ypres
The Second Battle of Ypres was the first time Germany used poison gas on a large scale on the Western Front in the First World War and the first time a former colonial force pushed back a major European power on European soil, which occurred in the battle of St...

, Lieutenant Alexis Helmer was killed. At his graveside, his friend John McCrae
John McCrae
Lieutenant Colonel John Alexander McCrae was a Canadian poet, physician, author, artist and soldier during World War I and a surgeon during the Second Battle of Ypres...

, M.D., of Guelph
Guelph
Guelph is a city in Ontario, Canada.Guelph may also refer to:* Guelph , consisting of the City of Guelph, Ontario* Guelph , as the above* University of Guelph, in the same city...

, Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....

, Canada, wrote the memorable poem
In Flanders Fields
In Flanders Fields
"In Flanders Fields" is one of the most notable poems written during World War I, created in the form of a French rondeau. It has been called "the most popular poem" produced during that period...

as a salute to those who perished in the Great War. Published in Punch on 8 December 1915, it is still recited today, especially on Remembrance Day
Armistice Day
Armistice Day is on 11 November and commemorates the armistice signed between the Allies of World War I and Germany at Compiègne, France, for the cessation of hostilities on the Western Front of World War I, which took effect at eleven o'clock in the morning—the "eleventh hour of the eleventh day...

 and Memorial Day
Memorial Day
Memorial Day is a United States federal holiday observed on the last Monday of May. Formerly known as Decoration Day, it originated after the American Civil War to commemorate the fallen Union soldiers of the Civil War...

.

Liberty Memorial
Liberty Memorial
The Liberty Memorial, located in Kansas City, Missouri, USA, is a memorial to the fallen soldiers of World War I and houses the The National World War I Museum, as designated by the United States Congress in 2004.. Groundbreaking commenced November 1, 1921, and the city held a site dedication...

 in Kansas City, Missouri
Kansas City, Missouri
Kansas City, Missouri is the largest city in the U.S. state of Missouri and is the anchor city of the Kansas City Metropolitan Area, the second largest metropolitan area in Missouri. It encompasses in parts of Jackson, Clay, Cass, and Platte counties...

, is a United States memorial dedicated to all Americans who served in World War I. The site for the Liberty Memorial was dedicated on November 1, 1921. On this day, the supreme Allied commanders spoke to a crowd of more than 100,000 people. It was the only time in history these leaders were together in one place. In attendance were Lieutenant General Baron Jacques of Belgium; General Armando Diaz
Armando Diaz
Armando Diaz, 1st Duca della Vittoria was an Italian general and a Marshal of Italy.Born in Naples, Diaz began his military career as a student at the Military Academy of Turin, where he became an artillery officer. He was a colonel commanding the 93rd infantry during the Italo-Turkish War, and...

 of Italy; Marshal Ferdinand Foch
Ferdinand Foch
Ferdinand Foch , GCB, OM, DSO was a French soldier, war hero, military theorist, and writer credited with possessing "the most original and subtle mind in the French army" in the early 20th century. He served as general in the French army during World War I and was made Marshal of France in its...

 of France; General Pershing of the United States; and Admiral D. R. Beatty
David Beatty, 1st Earl Beatty
Admiral of the Fleet David Richard Beatty, 1st Earl Beatty, GCB, OM, GCVO, DSO was an admiral in the Royal Navy...

 of Great Britain. After three years of construction, the Liberty Memorial
Liberty Memorial
The Liberty Memorial, located in Kansas City, Missouri, USA, is a memorial to the fallen soldiers of World War I and houses the The National World War I Museum, as designated by the United States Congress in 2004.. Groundbreaking commenced November 1, 1921, and the city held a site dedication...

 was completed and President Calvin Coolidge
Calvin Coolidge
John Calvin Coolidge, Jr. was the 30th President of the United States . A Republican lawyer from Vermont, Coolidge worked his way up the ladder of Massachusetts state politics, eventually becoming governor of that state...

 delivered the dedication speech to a crowd of 150,000 people in 1926.

Liberty Memorial is also home to The National World War I Museum, the only museum dedicated solely to World War I in the United States.

Cultural memory

The First World War had a lasting impact on social memory. It was seen by many in Britain as signalling the end of an era of stability stretching back to the Victorian period
Victorian era
The Victorian era of British history was the period of Queen Victoria's reign from 20 June 1837 until her death on 22 January 1901. It was a long period of peace, prosperity, refined sensibilities and national self-confidence...

, and across Europe many regarded it as a watershed. Historian Samuel Hynes explained:
This has become the most common perception of the First World War, perpetuated by the art, cinema, poems, and stories published subsequently. Films such as All Quiet on the Western Front
All Quiet on the Western Front
All Quiet on the Western Front is a novel by Erich Maria Remarque, a German veteran of World War I. The book describes the German soldiers' extreme physical and mental stress during the war, and the detachment from civilian life felt by many of these soldiers upon returning home from the front.The...

, Paths of Glory
Paths of Glory
Paths of Glory is a 1957 American anti-war film by Stanley Kubrick based on the novel of the same name by Humphrey Cobb. Set during World War I, the film stars Kirk Douglas as Colonel Dax, the commanding officer of French soldiers who refused to continue a suicidal attack...

and King & Country
King & Country
King and Country is a 1964 British film, directed by American-born director Joseph Losey, shot in black and white, and starring Dirk Bogarde and Tom Courtenay...

have perpetuated the idea, while war-time films including Camrades, Flanders Poppies, and Shoulder Arms
Shoulder Arms
Shoulder Arms is Charlie Chaplin's second film for First National Pictures. Released in 1918, it is a silent comedy set in France during World War I. The main part of the film occurs in a dream. It co-starred Edna Purviance and Sydney Chaplin, Chaplin's brother...

 indicate that the most contemporary views of the war were overall far more positive. Likewise, the art of Paul Nash
Paul Nash (artist)
Paul Nash was a British landscape painter, surrealist and war artist, as well as a book-illustrator, writer and designer of applied art. He was the older brother of the artist John Nash.-Early life:...

, John Nash
John Nash (artist)
John Northcote Nash CBE RA was a British painter of landscape and still-life, wood-engraver and illustrator, particularly of botanic works.-Biography:...

, Christopher Nevison, and Henry Tonks
Henry Tonks
Henry Tonks, FRCS was a British draughtsman and painter of figure subjects, chiefly interiors, and a caricaturist...

 in Britain painted a negative view of the conflict in keeping with the growing perception, while popular war-time artists such as Muirhead Bone
Muirhead Bone
Sir Muirhead Bone was a Scottish etcher, drypoint and watercolour artist.The son of a printer, Bone was born in Glasgow and trained initially as an architect, later going on to study art at Glasgow School of Art. He began printmaking in 1898, and although his first known print was a lithograph, he...

 painted more serene and pleasant interpretations subsequently rejected as inaccurate. Several historians have since countered these interpretations:
These beliefs did not become widely shared because they offered the only accurate interpretation of wartime events. In every respect, the war was much more complicated than they suggest. In recent years, historians have argued persuasively against almost every popular cliché of the First World War. It has been pointed out that, although the losses were devastating, their greatest impact was socially and geographically limited. The many emotions other than horror experienced by soldiers in and out of the front line, including comradeship, boredom, and even enjoyment, have been recognised. The war is not now seen as a 'fight about nothing', but as a war of ideals, a struggle between aggressive militarism and more or less liberal democracy
Liberal democracy
Liberal democracy, also known as constitutional democracy, is a common form of representative democracy. According to the principles of liberal democracy, elections should be free and fair, and the political process should be competitive...

. It has been acknowledged that British generals were often capable men facing difficult challenges, and that it was under their command that the British army played a major part in the defeat of the Germans in 1918: a great forgotten victory.


Though these historians have discounted as "myths" these perceptions of the war, they are nevertheless prevalent across much of society. They have dynamically changed according to contemporary influences, reflecting in the 1950s perceptions of the war as 'aimless' following the contrasting Second World War, and emphasising conflict within the ranks during times of class conflict in the 1960s. The majority of additions to the contrary are often rejected.

Social trauma

The social trauma caused by unprecedented rates of casualties manifested itself in different ways, which have been the subject of subsequent historical debate. Some people were revolted by nationalism and its results, and began to work towards a more internationalist
Internationalism (politics)
Internationalism is a political movement which advocates a greater economic and political cooperation among nations for the theoretical benefit of all...

 world, supporting organisations such as the League of Nations
League of Nations
The League of Nations was an intergovernmental organization founded as a result of the Paris Peace Conference that ended the First World War. It was the first permanent international organization whose principal mission was to maintain world peace...

. Pacifism
Pacifism
Pacifism is the opposition to war and violence. The term "pacifism" was coined by the French peace campaignerÉmile Arnaud and adopted by other peace activists at the tenth Universal Peace Congress inGlasgow in 1901.- Definition :...

 became increasingly popular. Others had the opposite reaction, feeling that only strength and military might could be relied upon in a chaotic and inhumane world. Anti-modernist
Development criticism
Development criticism refers to criticisms of technological development.-Notable development critics:*Edward Abbey*John Africa*Stafford Beer *Charles A...

 views were an outgrowth of the many changes taking place in society.
The experiences of the war led to a collective trauma
Collective trauma
A collective trauma is a traumatic psychological effect shared by a group of people of any size, up to and including an entire society. Traumatic events witnessed by an entire society can stir up collective sentiment, often resulting in a shift in that society's culture and mass actions.Well known...

 shared by many from all participating countries. The optimism
Optimism
The Oxford English Dictionary defines optimism as having "hopefulness and confidence about the future or successful outcome of something; a tendency to take a favourable or hopeful view." The word is originally derived from the Latin optimum, meaning "best." Being optimistic, in the typical sense...

 of la belle époque
Belle Époque
The Belle Époque or La Belle Époque was a period in European social history that began during the late 19th century and lasted until World War I. Occurring during the era of the French Third Republic and the German Empire, it was a period characterised by optimism and new technological and medical...

 was destroyed, and those who had fought in the war were referred to as the Lost Generation
Lost Generation
The "Lost Generation" is a term used to refer to the generation, actually a cohort, that came of age during World War I. The term was popularized by Ernest Hemingway who used it as one of two contrasting epigraphs for his novel, The Sun Also Rises. In that volume Hemingway credits the phrase to...

. For years afterwards, people mourned the dead, the missing, and the many disabled. Many soldiers returned with severe trauma, suffering from shell shock
Combat stress reaction
Combat stress reaction , in the past commonly known as shell shock or battle fatigue, is a range of behaviours resulting from the stress of battle which decrease the combatant's fighting efficiency. The most common symptoms are fatigue, slower reaction times, indecision, disconnection from one's...

 (also called neurasthenia, now called posttraumatic stress disorder). Many more returned home with few after-effects; however, their silence about the war contributed to the conflict's growing mythological status. In the United Kingdom, mass mobilisation, large casualty rates, and the collapse of the Edwardian era made a strong impression on society. Though many participants did not share in the experiences of combat or spend any significant time at the front, or had positive memories of their service, the images of suffering and trauma became the widely shared perception. Such historians as Dan Todman, Paul Fussell, and Samuel Heyns have all published works since the 1990s arguing that these common perceptions of the war are factually incorrect.

Discontent in Germany

The rise of Nazism
Nazism
Nazism, the common short form name of National Socialism was the ideology and practice of the Nazi Party and of Nazi Germany...

 and fascism included a revival of the nationalist spirit and a rejection of many post-war changes. Similarly, the popularity of the Stab-in-the-back legend (German: Dolchstoßlegende) was a testament to the psychological state
Mental health
Mental health describes either a level of cognitive or emotional well-being or an absence of a mental disorder. From perspectives of the discipline of positive psychology or holism mental health may include an individual's ability to enjoy life and procure a balance between life activities and...

 of defeated Germany and was a rejection of responsibility for the conflict. This conspiracy theory
Conspiracy theory
A conspiracy theory explains an event as being the result of an alleged plot by a covert group or organization or, more broadly, the idea that important political, social or economic events are the products of secret plots that are largely unknown to the general public.-Usage:The term "conspiracy...

 of betrayal became common, and the German populace came to see themselves as victims. The
Dolchstoßlegendes popular acceptance in Germany played a significant role in the rise of Nazism. A sense of disillusionment and cynicism
Cynicism
Cynicism , in its original form, refers to the beliefs of an ancient school of Greek philosophers known as the Cynics . Their philosophy was that the purpose of life was to live a life of Virtue in agreement with Nature. This meant rejecting all conventional desires for wealth, power, health, and...

 became pronounced, with nihilism
Nihilism
Nihilism is the philosophical doctrine suggesting the negation of one or more putatively meaningful aspects of life. Most commonly, nihilism is presented in the form of existential nihilism which argues that life is without objective meaning, purpose, or intrinsic value...

 growing. Many believed the war heralded the end of the world as they had known it because of the high fatalities among a generation of men, the dissolution of governments and empires, and the collapse of capitalism and imperialism
Imperialism
Imperialism, as defined by Dictionary of Human Geography, is "the creation and/or maintenance of an unequal economic, cultural, and territorial relationships, usually between states and often in the form of an empire, based on domination and subordination." The imperialism of the last 500 years,...

.

Communist and socialist movements around the world drew strength from this theory and enjoyed a new level of popularity. These feelings were most pronounced in areas directly or harshly affected by the war. Out of German discontent with the still controversial Treaty of Versailles
Treaty of Versailles
The Treaty of Versailles was one of the peace treaties at the end of World War I. It ended the state of war between Germany and the Allied Powers. It was signed on 28 June 1919, exactly five years after the assassination of Archduke Franz Ferdinand. The other Central Powers on the German side of...

, Adolf Hitler
Adolf Hitler
Adolf Hitler was an Austrian-born German politician and the leader of the National Socialist German Workers Party , commonly referred to as the Nazi Party). He was Chancellor of Germany from 1933 to 1945, and head of state from 1934 to 1945...

 was able to gain popularity and power. World War II was in part a continuation of the power struggle never fully resolved by the First World War; in fact, it was common for Germans in the 1930s and 1940s to justify acts of international aggression because of perceived injustices imposed by the victors of the First World War.

The establishment of the modern state of Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...

 and the roots of the continuing Israeli-Palestinian Conflict
Israeli-Palestinian conflict
The Israeli–Palestinian conflict is the ongoing conflict between Israelis and Palestinians. The conflict is wide-ranging, and the term is also used in reference to the earlier phases of the same conflict, between Jewish and Zionist yishuv and the Arab population living in Palestine under Ottoman or...

 are partially found in the unstable power dynamics of the Middle East which resulted from World War I. Prior to the end of the war, the Ottoman Empire
Ottoman Empire
The Ottoman EmpireIt was usually referred to as the "Ottoman Empire", the "Turkish Empire", the "Ottoman Caliphate" or more commonly "Turkey" by its contemporaries...

 had maintained a modest level of peace and stability throughout the Middle East. With the fall of the Ottoman government, power vacuums developed and conflicting claims to land and nationhood began to emerge. The political boundaries drawn by the victors of the First World War were quickly imposed, sometimes after only cursory consultation with the local population. In many cases, these continue to be problematic in the 21st-century struggles for national identity
National identity
National identity is the person's identity and sense of belonging to one state or to one nation, a feeling one shares with a group of people, regardless of one's citizenship status....

. While the dissolution of the Ottoman Empire
Ottoman Empire
The Ottoman EmpireIt was usually referred to as the "Ottoman Empire", the "Turkish Empire", the "Ottoman Caliphate" or more commonly "Turkey" by its contemporaries...

 at the end of World War I was pivotal in contributing to the modern political situation of the Middle East, including the Arab-Israeli conflict
Arab–Israeli conflict
The Arab–Israeli conflict refers to political tensions and open hostilities between the Arab peoples and the Jewish community of the Middle East. The modern Arab-Israeli conflict began with the rise of Zionism and Arab Nationalism towards the end of the nineteenth century, and intensified with the...

, the end of Ottoman rule also spawned lesser known disputes over water and other natural resources.

Views in the United States

U.S. intervention in the war, as well as the Wilson administration itself, became deeply unpopular. This was reflected in the U.S. Senate's rejection of the Versailles Treaty and membership in the League of Nations
League of Nations
The League of Nations was an intergovernmental organization founded as a result of the Paris Peace Conference that ended the First World War. It was the first permanent international organization whose principal mission was to maintain world peace...

. In the interwar era, a consensus arose that U.S. intervention had been a mistake, and the Congress passed laws in an attempt to preserve U.S. neutrality in any future conflict. Polls taken in 1937 and the opening months of World War II established that nearly 60% regarded intervention in WWI as a mistake, with only 28% opposing that view. But, in the period between the fall of France and the attack on Pearl Harbor
Attack on Pearl Harbor
The attack on Pearl Harbor was a surprise military strike conducted by the Imperial Japanese Navy against the United States naval base at Pearl Harbor, Hawaii, on the morning of December 7, 1941...

, public opinion changed dramatically and, for the first time, a narrow plurality rejected the idea that the war had been a mistake.

New national identities

Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

 reemerged as an independent country, after more than a century. As a "minor Entente nation" and the country with the most casualties per capita, the Kingdom of Serbia
Kingdom of Serbia
The Kingdom of Serbia was created when Prince Milan Obrenović, ruler of the Principality of Serbia, was crowned King in 1882. The Principality of Serbia was ruled by the Karađorđevic dynasty from 1817 onwards . The Principality, suzerain to the Porte, had expelled all Ottoman troops by 1867, de...

 and its dynasty became the backbone of the new multinational state, the Kingdom of Serbs, Croats and Slovenes (later renamed Yugoslavia
Yugoslavia
Yugoslavia refers to three political entities that existed successively on the western part of the Balkans during most of the 20th century....

). Czechoslovakia
Czechoslovakia
Czechoslovakia or Czecho-Slovakia was a sovereign state in Central Europe which existed from October 1918, when it declared its independence from the Austro-Hungarian Empire, until 1992...

, combining the Kingdom of Bohemia
Kingdom of Bohemia
The Kingdom of Bohemia was a country located in the region of Bohemia in Central Europe, most of whose territory is currently located in the modern-day Czech Republic. The King was Elector of Holy Roman Empire until its dissolution in 1806, whereupon it became part of the Austrian Empire, and...

 with parts of the Kingdom of Hungary
Kingdom of Hungary
The Kingdom of Hungary comprised present-day Hungary, Slovakia and Croatia , Transylvania , Carpatho Ruthenia , Vojvodina , Burgenland , and other smaller territories surrounding present-day Hungary's borders...

, became a new nation. Russia became the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 and lost Finland
Finland
Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...

, Estonia
Estonia
Estonia , officially the Republic of Estonia , is a state in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by Lake Peipsi and the Russian Federation . Across the Baltic Sea lies...

, Lithuania
Lithuania
Lithuania , officially the Republic of Lithuania is a country in Northern Europe, the biggest of the three Baltic states. It is situated along the southeastern shore of the Baltic Sea, whereby to the west lie Sweden and Denmark...

, and Latvia
Latvia
Latvia , officially the Republic of Latvia , is a country in the Baltic region of Northern Europe. It is bordered to the north by Estonia , to the south by Lithuania , to the east by the Russian Federation , to the southeast by Belarus and shares maritime borders to the west with Sweden...

, which became independent countries. The Ottoman Empire
Ottoman Empire
The Ottoman EmpireIt was usually referred to as the "Ottoman Empire", the "Turkish Empire", the "Ottoman Caliphate" or more commonly "Turkey" by its contemporaries...

 was soon replaced by Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...

 and several other countries in the Middle East.

In the British Empire, the war unleashed new forms of nationalism. In Australia and New Zealand the Battle of Gallipoli became known as those nations' "Baptism of Fire". It was the first major war in which the newly established countries fought, and it was one of the first times that Australian troops fought as Australians, not just subjects of the British Crown. Anzac Day
ANZAC Day
Anzac Day is a national day of remembrance in Australia and New Zealand, commemorated by both countries on 25 April every year to honour the members of the Australian and New Zealand Army Corps who fought at Gallipoli in the Ottoman Empire during World War I. It now more broadly commemorates all...

, commemorating the Australian and New Zealand Army Corps
Australian and New Zealand Army Corps
The Australian and New Zealand Army Corps was a First World War army corps of the Mediterranean Expeditionary Force that was formed in Egypt in 1915 and operated during the Battle of Gallipoli. General William Birdwood commanded the corps, which comprised troops from the First Australian Imperial...

, celebrates this defining moment.

After the Battle of Vimy Ridge
Battle of Vimy Ridge
The Battle of Vimy Ridge was a military engagement fought primarily as part of the Battle of Arras, in the Nord-Pas-de-Calais region of France, during the First World War. The main combatants were the Canadian Corps, of four divisions, against three divisions of the German Sixth Army...

, where the Canadian divisions fought together for the first time as a single corps, Canadians began to refer to theirs as a nation "forged from fire". Having succeeded on the same battleground where the "mother countries" had previously faltered, they were for the first time respected internationally for their own accomplishments. Canada entered the war as a Dominion of the British Empire and remained so, although she emerged with a greater measure of independence. While the other Dominions were represented by Britain, Canada was an independent negotiator and signatory of the Versailles Treaty.

Economic effects

One of the most dramatic effects of the war was the expansion of governmental powers and responsibilities in Britain, France, the United States, and the Dominions of the British Empire. In order to harness all the power of their societies, governments created new ministries and powers. New taxes were levied and laws enacted, all designed to bolster the war effort
War effort
In politics and military planning, a war effort refers to a coordinated mobilization of society's resources—both industrial and human—towards the support of a military force...

; many have lasted to this day. Similarly, the war strained the abilities of some formerly large and bureaucratised governments, such as in Austria–Hungary and Germany; however, any analysis of the long-term effects were clouded by the defeat of these governments.
Gross domestic product
Gross domestic product
Gross domestic product refers to the market value of all final goods and services produced within a country in a given period. GDP per capita is often considered an indicator of a country's standard of living....

 (GDP) increased for three Allies (Britain, Italy, and U.S.), but decreased in France and Russia, in neutral Netherlands, and in the three main Central Powers. The shrinkage in GDP in Austria, Russia, France, and the Ottoman Empire reached 30 to 40%. In Austria, for example, most pigs were slaughtered, so at war's end there was no meat.
In all nations the government's share of GDP increased, surpassing fifty percent in both Germany and France and nearly reaching that level in Britain. To pay for purchases in the United States, Britain cashed in its extensive investments in American railroads and then began borrowing heavily on Wall Street
Wall Street
Wall Street refers to the financial district of New York City, named after and centered on the eight-block-long street running from Broadway to South Street on the East River in Lower Manhattan. Over time, the term has become a metonym for the financial markets of the United States as a whole, or...

. President Wilson was on the verge of cutting off the loans in late 1916, but allowed a great increase in U.S. government
Federal government of the United States
The federal government of the United States is the national government of the constitutional republic of fifty states that is the United States of America. The federal government comprises three distinct branches of government: a legislative, an executive and a judiciary. These branches and...

 lending to the Allies. After 1919, the U.S. demanded repayment of these loans. The repayments were, in part, funded by German reparations, which, in turn, were supported by American loans to Germany. This circular system collapsed in 1931 and the loans were never repaid. In 1934, Britain owed the US $4.4 billion
1000000000 (number)
1,000,000,000 is the natural number following 999,999,999 and preceding 1,000,000,001.In scientific notation, it is written as 109....

 of World War I debt.

Macro- and micro-economic consequences devolved from the war. Families were altered by the departure of many men. With the death or absence of the primary wage earner, women were forced into the workforce in unprecedented numbers. At the same time, industry needed to replace the lost labourers sent to war. This aided the struggle for voting rights for women
Suffragette
"Suffragette" is a term coined by the Daily Mail newspaper as a derogatory label for members of the late 19th and early 20th century movement for women's suffrage in the United Kingdom, in particular members of the Women's Social and Political Union...

.

In Britain, rationing was finally imposed in early 1918, limited to meat, sugar, and fats (butter and oleo
Margarine
Margarine , as a generic term, can indicate any of a wide range of butter substitutes, typically composed of vegetable oils. In many parts of the world, the market share of margarine and spreads has overtaken that of butter...

), but not bread. The new system worked smoothly. From 1914 to 1918 trade union membership doubled, from a little over four million to a little over eight million. Work stoppages and strikes became frequent in 1917–1918 as the unions expressed grievances regarding prices, alcohol control, pay disputes, fatigue from overtime and working on Sundays, and inadequate housing.

Britain turned to her colonies for help in obtaining essential war materials whose supply had become difficult from traditional sources. Geologists such as Albert Ernest Kitson
Albert Ernest Kitson
Sir Albert Ernest Kitson KBE, CMG was a British/Australian geologist and naturalist, winner of the Lyell Medal in 1927.-Early life:...

 were called upon to find new resources of precious minerals in the African colonies. Kitson discovered important new deposits of manganese
Manganese
Manganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a free element in nature , and in many minerals...

, used in munitions production, in the Gold Coast
Gold Coast (region)
The Gold Coast was the region of West Africa which is now the nation of Ghana. Early uses of the term refer literally to the coast and not the interior. It was not until the 19th century that the term came to refer to areas that are far from the coast...

.

Article 231
Article 231 of the Treaty of Versailles
Article 231, commonly known as the "Guilt Clause" or the "War Guilt Clause", is the first article in Part VIII, "Reparations" of the Treaty of Versailles. Apart from "Article 231", there is no title for this article in the treaty itself...

 of the Treaty of Versailles
Treaty of Versailles
The Treaty of Versailles was one of the peace treaties at the end of World War I. It ended the state of war between Germany and the Allied Powers. It was signed on 28 June 1919, exactly five years after the assassination of Archduke Franz Ferdinand. The other Central Powers on the German side of...

 (the so-called "war guilt" clause) declared Germany and its allies responsible for all "loss and damage" suffered by the Allies during the war and provided the basis for reparations
World War I reparations
World War I reparations refers to the payments and transfers of property and equipment that Germany was forced to make under the Treaty of Versailles following its defeat during World War I...

. The total reparations demanded was 132 billion gold marks, which was far more than the total German gold or foreign exchange. The economic problems that the payments brought, and German resentment at their imposition, are usually cited as one of the more significant factors that led to the end of the Weimar Republic
Weimar Republic
The Weimar Republic is the name given by historians to the parliamentary republic established in 1919 in Germany to replace the imperial form of government...

 and the beginning of the dictatorship of Adolf Hitler
Adolf Hitler
Adolf Hitler was an Austrian-born German politician and the leader of the National Socialist German Workers Party , commonly referred to as the Nazi Party). He was Chancellor of Germany from 1933 to 1945, and head of state from 1934 to 1945...

. After Germany’s defeat in World War II, payment of the reparations was not resumed. There was, however, outstanding German debt that the Weimar Republic had used to pay the reparations. Germany finished paying off the reparations in October 2010.

See also

  • European Civil War
    European Civil War
    The European Civil War is a term that is used to characterise both World War I and World War II and the inter-war period as a protracted civil war taking place in Europe. It is used in referring to the repeated confrontations that occurred during the first-half of the 20th century...

  • List of last surviving World War I veterans by country
  • List of people associated with World War I
  • List of surviving veterans of World War I
  • List of wars and anthropogenic disasters by death toll
  • Lists of wars
  • Lists of World War I topics
  • World War I casualties
    World War I casualties
    The total number of military and civilian casualties in World War I were over 35 million. There were over 15 million deaths and 20 million wounded ranking it among the deadliest conflicts in human history....

  • World War One – Medal Abbreviations

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