966. Poland's Duke Mieszko I is baptized and Poland accepts Christianity.
1025. Boleslaw is crowned the first king of Poland.
1385. The commonwealth of Poland and Lithuania is created through a treaty.
1683. King Jan Sobieski III defeats the army of the Ottoman Empire in the battle of Vienna.
1772. Poland is partitioned (divided) by Russia, Austria, and Prussia.
1795. Polish-American hero Tadeusz Kosciuszko leads an insurrection against Russia, one of many that occur as Poland loses all the functionings of an independent state as it is subsumed into the partitioning countries. Poland ceases to exist as an independent nation until 1918.
1918. Poland is reborn at the end of World War I; Ignacy Paderewski becomes the first prime minister.
1920. Poland fights a war with the Soviet Union and successfully defends itself against the Red Army.
1939. On 1 September Nazi Germany invades Poland signaling the beginning of World War II; on 17 September Russian leader Josef Stalin orders the Red Army to enter Poland in accordance with the secret treaty between the Soviet Union and Germany; Poland is occupied until 1945.
1940. The Polish government-in-exile formed in the United Kingdom organizes a system of military and civilian communication in occupied Poland.
1945. Warsaw is liberated and Poland is freed of Nazi occupation.
1948. The Soviet Union installs a communist government in Poland, leading to over 40 years of centrally-planned economic organization.
1956. In June, protests against Soviet control in the city of Poznan end with nearly 80 dead; by October, the ruling regime installs new leadership and temporarily relaxes some controls.
1970. The December protests of shipyard workers against food price increases lead to violent action by government security forces in the Baltic cities of Szczecin, Gdynia, and Gdansk.
1976. Following another wave of protests, the Polish opposition forms the Committee for Workers' Defense and begins to organize the underground publication of officially banned writers and intellectuals.
1979. Polish Cardinal Karol Wojtyla, the Roman Catholic Archbishop of Cracow, is elected Pope John Paul II.
1980. The independent trade union "Solidarity," led by Lech Walesa, is born in Gdansk.
1981. Martial law is introduced on 13 December, and there are widespread arrests of Solidarity activists.
1989. Negotiations lead to a peaceful transfer of power to the opposition; the first free elections are held in Poland since the end of World War II.
1997. A new constitution is adopted in a nationwide referendum.
1999. Poland joins the North Atlantic Treaty Organization (NATO).