Vladimir Ilyich Lenin, born Vladimir Ilyich Ulyanov (22 April 1870 - 21 January 1924) was a Russian communist revolutionary, politician and political theorist. Lenin served as the leader of the Russian Soviet Federative Socialist Republic from 1917, and then concurrently as Premier of the Soviet Union from 1922, until his death. Under his administration, the Russian Empire disintegrated and was replaced by the Soviet Union, a single-party constitutionally socialist state; all wealth including land, industry and business were nationalised. Based in Marxism, his theoretical contributions to Marxist thought are known as Leninism.