People's Republic of Bulgaria

The People's Republic of Bulgaria (PRB; Bulgarian: Народна република България (НРБ) Narodna republika Balgariya (NRB)) was the official name of the Bulgarian socialist republic that existed from 1946 to 1990, when the Bulgarian Communist Party (BCP) ruled together with its coalition partner, the Bulgarian Agrarian National Union. Bulgaria was an Eastern Bloc country, part of Comecon, a member of the Warsaw Pact and closely allied with the Soviet Union during the Cold War.

More information on the Wikipedia page.