Warsaw Pact
From dKosopedia
In response to the perceived threat posed by the integration of remilitarized West Germany into NATO on May 9, 1955, the communist governments of Eastern Europe met in Warsaw and, on May 14, sign a "treaty of friendship, cooperation and mutual assistance". The participating nations were the Soviet Union, Poland, East Germany, Hungary, Czechoslovakia, Bulgaria, Romania and Albania. In actuality, all were puppet states of the Soviet Union.
The Warsaw Pact was invoked in 1956 and again in 1968 to suppress reform attempts in Hungary and Czechoslovakia. Albania allied itself with the communist government of China in 1961, but did not formally leave the Warsaw Pact until 1968.
The nations of the Warsaw Pact and NATO faced each other in the so-called Cold War for 35 years, until Mikhail Gorbachev's abandonment of the Brezhnev Doctrine led to the fall of communism in Eastern Europe in 1989. The Warsaw Pact was formally dissolved on July 1, 1991.