Byelorussian Soviet Socialist Republic
The Byelorussian Soviet Socialist Republic (BSSR), also known as the Byelorussian SSR, Byelorussia, or simply Belarus, was a communist state from 1920 to 1922 and then one of fifteen constituent republics of the Soviet Union (USSR) from 1922 to 1991, with its own legislation from 1990 to 1991. The republic was ruled by the Communist Party of Byelorussia.
Source: Wikipedia — Byelorussian Soviet Socialist Republic (CC BY-SA 4.0)