Excerpts from Books and Wikipedia
"The Warsaw Treaty Organization (WTO), officially the Treaty of Friendship, Cooperation and Mutual Assistance, commonly known as the Warsaw Pact (WP), was a collective defense treaty signed in Warsaw, Poland, between the Soviet Union and seven other Eastern Bloc socialist republics of Central and Eastern Europe in May 1955, during the Cold War. The Warsaw Pact was the military complement to the Council for Mutual Economic Assistance (CoMEcon), the regional economic organization for the socialist states of Central and Eastern Europe. The Warsaw Pact was created in reaction to the integration of West Germany into NATO in 1955 as per the London and Paris Conferences of 1954." [Wikipedia]