Ferdinand IV was King of the Romans

King of the Romans

King of the Romans was the title used by the ruler of the Holy Roman Empire following his election to the office by the princes of the Kingdom of Germany...

, King of Hungary, and King of Bohemiahttp://www.britannica.com/EBchecked/topic/204534/Ferdinand-IV.
He was born in 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...

, the eldest son of Ferdinand III, Holy Roman Emperor

Ferdinand III, Holy Roman Emperor

Ferdinand III was Holy Roman Emperor from 15 February 1637 until his death, as well as King of Hungary and Croatia, King of Bohemia and Archduke of Austria.-Life:...

 and his first wife Maria Ana of Spain. His maternal grandparents were Philip III of Spain

Philip III of Spain

Philip III , also known as Philip the Pious, was the King of Spain and King of Portugal and the Algarves, where he ruled as Philip II , from 1598 until his death...

 and Margaret of Austria.

He was an older brother of Mariana of Austria

Mariana of Austria

Mariana of Austria was Queen consort of Spain as the second wife of King Philip IV, who was also her maternal uncle...

 and Leopold I, Holy Roman Emperor

Leopold I, Holy Roman Emperor

| style="float:right;" | Leopold I was a Holy Roman Emperor, King of Hungary and King of Bohemia. A member of the Habsburg family, he was the second son of Emperor Ferdinand III and his first wife, Maria Anna of Spain. His maternal grandparents were Philip III of Spain and Margaret of Austria...

.

He was made King of Bohemia in 1646, King of 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...

 in 1647 (coronation took place on June 16 in Pressburg) and was elected King of the Romans (future ruler of the Holy Roman Empire

Holy Roman Empire

The Holy Roman Empire was a realm that existed from 962 to 1806 in Central Europe.It was ruled by the Holy Roman Emperor. Its character changed during the Middle Ages and the Early Modern period, when the power of the emperor gradually weakened in favour of the princes...

) on May 31, 1653, and crowned at Ratisbon (Regensburg

Regensburg

Regensburg is a city in Bavaria, Germany, located at the confluence of the Danube and Regen rivers, at the northernmost bend in the Danube. To the east lies the Bavarian Forest. Regensburg is the capital of the Bavarian administrative region Upper Palatinate...

) on June 18 of the same year. He died in Vienna, predeceasing his father, leaving his younger brother, the future Leopold I, Holy Roman Emperor

Leopold I, Holy Roman Emperor

| style="float:right;" | Leopold I was a Holy Roman Emperor, King of Hungary and King of Bohemia. A member of the Habsburg family, he was the second son of Emperor Ferdinand III and his first wife, Maria Anna of Spain. His maternal grandparents were Philip III of Spain and Margaret of Austria...

, as heir. He died of smallpox

Smallpox

Smallpox was an infectious disease unique to humans, caused by either of two virus variants, Variola major and Variola minor. The disease is also known by the Latin names Variola or Variola vera, which is a derivative of the Latin varius, meaning "spotted", or varus, meaning "pimple"...

.