The name of the military alliance that held the east European countries together was the Warsaw Pact. It was a mutual defense treaty signed on May 14, 1955, by the Soviet Union and several of its satellite states in response to the creation of the North Atlantic Treaty Organization (NATO) by the Western powers.

The Warsaw Pact was established as a direct response to NATO's presence and was aimed at countering the perceived threat from the capitalist countries of Western Europe, particularly the United States. The member countries of the Warsaw Pact included the Soviet Union, Albania, Bulgaria, Czechoslovakia, East Germany, Hungary, Poland, and Romania.

The key points regarding the Warsaw Pact are as follows:

1. Formation: The Warsaw Pact was formed in response to the growing influence of NATO in Europe. It was seen as a way to consolidate the communist bloc and strengthen the Soviet Union's control over its satellite states.

2. Mutual Defense: The main objective of the Warsaw Pact was to provide collective security and defense for its member states. It stipulated that an attack on one member would be considered an attack on all, and the member countries would come to each other's aid if necessary.

3. Soviet Dominance: The Warsaw Pact was primarily led by the Soviet Union, which held significant control over the military forces and decision-making within the alliance. The Soviet Union maintained a strong influence over its satellite states, ensuring their loyalty and cooperation.

4. Cold War Dynamics: The Warsaw Pact and NATO represented the two opposing sides of the Cold War, with the Soviet Union and its allies on one side and the United States and its allies on the other. The existence of these alliances contributed to the division of Europe into two ideological blocs.

5. Dissolution: The Warsaw Pact remained intact throughout the Cold War but started to disintegrate in the late 1980s as the Soviet Union faced internal and economic struggles. It officially dissolved on July 1, 1991, as the Soviet Union itself began to unravel.

In conclusion, the Warsaw Pact was a military alliance formed by the Soviet Union and its satellite states to counter the influence of NATO. It played a significant role in shaping the geopolitical dynamics of the Cold War era in Europe.