The Soviet Union was formed in 1922 following a bloody civil war that was itself sparked by Russia's defeat in the First Great War of 1914-1919. Following the overthrow of Czar Nicholas II and the institution of a provisional government, Bolshevik forces attempted to seize control of the government. Although opposed by anti-communist "White Russian" forces for many years and plagued by internal strife, the Reds won out and established the USSR after half a decade of brutal fighting.