The Russian Empire functioned as an absolute monarchy on the ideological doctrine of Orthodoxy, Autocracy, and Nationality until the Revolution of 1905, when a nominal semi-constitutional monarchy was established. It functioned poorly during World War I, leading to the February Revolution and the abdication of Tsar Nicholas II, in which the monarchy was abolished. In the October Revolution, the Bolsheviks seized power, leading to the Russian Civil War. The Bolsheviks executed the imperial family in 1918 and established the Soviet Union in 1922 after emerging victorious in the civil war.