1946: Communists emerge as strongest party in elections, and head a coalition government. Eduard Benes, a noncommunist, is president.
1948: Communists force resignation of Mr. Benes; a ``people's republic'' is proclaimed.
1950: Communist Party purge seeks to establish Stalinist ideological purity.
1967: Demands grow, particularly among students and the intelligentsia, for a higher standard of living and greater personal freedom.
January 1968: Alexander Dubcek becomes first secretary of the Communist Party; ``Prague Spring'' liberalization begins.
August 1968: Soviet Union and Warsaw Pact allies invade. Mr. Dubcek is stripped of power. Hard-liner Gustav Husak is installed as leader.
January 1977: Dissent erupts again with Charter 77, in which members of the intelligentsia air grievances. A government crackdown follows.
December 1987: Milos Jakes replaces Gustav Husak as party chief.
Nov. 12, 1989: With political turmoil sweeping Eastern Europe, Mr. Jakes tells a Communist youth conference that the party will not tolerate street protests.
Nov. 17: Tens of thousands of protesters rally in the largest antigovernment demonstration since 1968. The protest is crushed.
Nov. 19: In another large demonstration, Prague protesters denounce police brutality. Opposition groups, including some Communists, form Civic Forum.
Nov. 20: Hundreds of thousands of demonstrators demand free elections and the resignation of leaders. Protest spreads to other cities.
Nov. 24: The Communist leadership, headed by Jakes, resigns. Mr. Dubcek returns to Prague and addresses a huge crown in Wenceslas Square.
Dec. 28: Dubcek is unanimously elected chairman of the National Parliament.