The 1917 Russian Revolution resulted in the overthrow of the monarchy of Czar Nicholas II, the rise to power of the Russian Bolsheviks led by Vladimir Lenin and the withdrawal of Russia from World War I. A civil war in Russia followed the revolution as the supporters of the old czarist regime, the "whites," struggled with the new Bolshevik powers, the "reds," for control. The Bolsheviks won the civil war and Russia became the Soviet Union, or U.S.S.R., in 1922.
Russia became the world's first country ruled by a centralized socialist government with Lenin as its head of state. After Lenin's death in 1924, Joseph Stalin gained control of the Russian government and remained in power until his death in 1953. His rule over Russia, during which his policies resulted in the loss of millions of lives, is considered by many historians to be one of the most brutal dictatorships in the modern world.