Vladimir Ilyich Lenin ; born Vladimir Ilyich Ulyanov (22 April] 1870 – 21 January 1924) was a Russian communist revolutionary, politician and political theorist. He served as the leader of the Russian SFSR from 1917, and then concurrently as Premier of the Soviet Union from 1922, until his death. Politically a Marxist, his theoretical contributions to Marxist thought are known as Leninism, which coupled with Marxian economic theory have collectively come to be known as Marxism–Leninism. As the leader of the Bolshevik faction of the Russian Social Democratic Labour Party, he took a senior role in orchestrating the October Revolution in 1917, which led to the overthrow of the Russian Provisional Government and the establishment of the Russian Socialist Federative Soviet Republic, the world's first constitutionally socialist state. Lenin had a significant influence on the international Communist movement and was one of the most important figures of the 20th century.