'Vladimir Ilyich Ulyanov ( 1870 – 21 January 1924), better known as Vladimir Lenin', was a Russian lawyer, revolutionary, politician and political theorist who served as the first and founding head of government of Soviet Russia from 1917 to 1924 and of the Soviet Union from 1922 to 1924. Under his administration, Russia, and later the Soviet Union, became a one-party socialist state governed by the Communist Party over the course of the Russian Civil War. Ideologically a Marxist, his development of the ideology is known as Leninism.
Born into an upper-middle-class family in Simbirsk, Lenin embraced revolutionary socialist politics following his brother's 1887 execution. Expelled from Kazan Imperial University for participating in protests against the Russian Empire's Tsarist government, he devoted the following years to a law degree. He moved to Saint Petersburg in 1893 and became a senior Marxist activist. In 1897, he was arrested for sedition and exiled to Shushenskoye in Siberia for three years, where he married Nadezhda Krupskaya. After his exile, he moved to Western Europe, where he became a prominent theorist in the Marxist Russian Social Democratic Labour Party (RSDLP). In 1903, he took a key role in the RSDLP ideological split, leading the Bolshevik faction against Julius Martov's Mensheviks. Following Russia's failed Revolution of 1905, he campaigned for the First World War to be transformed into a Europe-wide proletarian revolution, which, as a Marxist, he believed would cause the overthrow of capitalism and its replacement with socialism. After the 1917 February Revolution ousted the Tsar and established a Provisional Government, he returned to Russia to play a leading role in the October Revolution in which the Bolsheviks overthrew the new regime.
Lenin's Bolshevik government initially shared power with the Left Socialist Revolutionaries, elected soviets, and a multi-party Constituent Assembly, although by 1918 it had centralised power in the new Communist Party.