formed Soviet Union Russian SFSR Byelorussian Transcaucasian Ukrainian 15 republics Russian
On 30 December 1922, Lenin and his aides formed the Soviet Union, by joining the Russian SFSR into a single state with the Byelorussian, Transcaucasian, and Ukrainian republics. Eventually internal border changes and annexations during World War II created a union of 15 republics; the largest in size and population being the Russian SFSR, which dominated the union for its entire history politically, culturally, and economically.
