The Premier of the Soviet Union (Russian: Глава Правительства СССР) was the head of government of the Union of Soviet Socialist Republics (USSR). The office had four different names throughout its existence: Chairman of the Council of People's Commissars (1923–1946), Chairman of the Council of Ministers (1946–1991), Prime Minister (January – August 1991) and Chairman of the Committee on the Operational Management of the Soviet Economy (August–December 1991). Long before 1991, most non-Soviet sources referred to the post as "Premier" or "Prime Minister."