The First Austrian Democratic Republic (German: Österreich Demokratische Republik) was a country in the Warsaw Pact and Union of Republics that existed between the signing of the Yalta Treaty in April of 1945—the agreement after the end of World War II which freed Austria from Nazi rule—and ended to with the establishment of a the Democratic Republic of Austria-Hungary. The period was marked by sour relations with Bavaria due to the loss of territories to them after the Treaty of Yalta.
The nation was administered by the Communist Party of Austria from 1946 until its merger with the Hungarian Socialist Workers' Party in 1958 to form the Austro-Hungarian Socialist Unity Party which ruled the Democratic Republic of Austria-Hungary from 1958 until its inherit collapse 10 years later, leading to the disintegration of the party, and culminating into the collapse of communism itself in both Austria and Hungary.