966 Christianisation of Poland
1651 The Battle of Beresteczko between Poland and Ukraine starts.
1660 Treaty of Oliwa is established between Sweden and Poland.
1918 Poland declares its independence from Russia.
1918 The Second Polish Republic is proclaimed in Poland.
1918 Józef Piłsudski comes to Warsaw and assumes supreme military power in Poland. Poland regains its independence, celebrated each year on this day.
1919 Ignacy Jan Paderewski becomes Prime Minister of the newly independent Poland.
1922 Gabriel Narutowicz is announced the first president of Poland.
1939 World War II: Germany and the Soviet Union sign a non-aggression treaty, the Molotov-Ribbentrop Pact. In a secret addition to the pact, the Baltic states, Finland, Romania, and Poland are divided between the two nations.
1942 World War II: In Poland, the first female prisoners arrive at Auschwitz.
1943 World War II: The discovery of a mass grave of Polish prisoners of war executed by Soviet forces in the Katyń Forest Massacre is announced, alienating the Western Allies, the Polish government in exile in London, from the Soviet Union.
1943 Prisoners at the Nazi German Sobibor extermination camp in Poland revolted against the Germans, killing eleven SS troops who were guards there, and wounding many more. About 300 of the Sobibor Camp's 600 prisoners escaped from this Nazi extermination camp, and about 50 of these survived past the end of World War II (on May 8, 1945, European time).
1944 World War II: Approximately 38 men, women, and children die in the Koniuchy massacre in Poland.
1945 The Soviet Union recognizes the new pro-Soviet government of Poland.
1980 After weeks of strikes at the Lenin Shipyard in Gdańsk, Poland, the nationwide independent trade union Solidarity is established.
1980 Government of Poland legalizes Solidarity trade union
1982 Poland bans Solidarity and all trade unions.
1989 The Round Table Talks start in Poland, thus marking the beginning of overthrow of communism in Eastern Europe.
1989 Solidarity's victory in the first (somewhat) free parliamentary elections in post-war Poland sparks off a succession of peaceful anti-communist revolutions in Eastern Europe, leads to the creation of the so-called Contract Sejm and begins the Autumn of Nations.
1993 Last Russian troops leave Poland.
2002 Enlargement of the European Union: The European Union announces that Cyprus, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia, and Slovenia will become members from May 1, 2004.