Respuesta :

jewulashane24
The Union of Soviet Socialist Republics (USSR) was founded in November 1917 by the Bolshevik Party. Led by Vladimir Lenin and, after 1923, by Josef Stalin, the Bolsheviks 
established Communist rule in the former Russian Empire after the conclusion of a bitter civil war in 1921.
nitijanie
The previous answer is much more detailed so be sure to look at that
:))). In summary, it was in result after overthrowing the monarchy and the czar