The 1955 military alliance of Soviet-led Eastern Bloc nations was the Warsaw Pact. Its formal name was the Treaty of Friendship, Cooperation and Mutual Assistance, signed in Warsaw, Poland, on May 14, 1955.
The Soviet Union formed the alliance with Albania, Bulgaria, Czechoslovakia, East Germany, Hungary, Poland, and Romania. It was created soon after West Germany joined NATO, reflecting Cold War fears that a rearmed West Germany would strengthen the Western military bloc. Although described as a mutual-defense organization, the Soviet Union dominated its command structure and strategic decisions.
The Warsaw Pact was NATO’s principal military counterpart in Europe. Its members did not fight NATO directly in a conventional European war, but the alliance played a major role in maintaining Soviet influence over Eastern Europe. Warsaw Pact forces intervened in Hungary in 1956 and Czechoslovakia in 1968 to suppress challenges to communist rule.
The pact should not be confused with Comecon, which was the Eastern Bloc’s economic organization. The Warsaw Pact was military and political, while Comecon coordinated trade and economic planning. The alliance effectively ended in 1991 as communist governments collapsed across Eastern Europe.