Why Poland did not want to release Soviet troops Tomorrow marks 55 years since the Treaty of Friendship, Cooperation and Mutual Assistance, known as the Warsaw Pact, was signed on May 14, 1955 in Warsaw. The document was signed by representatives of Albania, Bulgaria, Hungary, East Germany, Poland, Romania, the Soviet Union and Czechoslovakia. The military alliance of socialist countries was intended to balance the NATO bloc - just in May 1955, West Germany joined the ranks of the alliance.