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.
Born to a wealthy middle-class family in Simbirsk, Lenin gained an interest in revolutionary leftist politics following the execution of his brother in 1887. Briefly attending the University of Kazan, he was ejected for his involvement in anti-Tsarist protests, devoting the following years to gaining a law degree and to radical politics, becoming a Marxist. In 1893 he moved to St. Petersburg, becoming a senior figure within the League of Struggle for the Emancipation of the Working Class. Arrested for sedition and exiled to Siberia for three years, he married Nadezhda Krupskaya, and fled to Western Europe, living in Germany, England and Switzerland. Following the February Revolution of 1917, in which the Tsar was overthrown and a provisional government took power, he returned home.
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. Immediately afterwards, Lenin proceeded to implement socialist reforms, including the transfer of estates and crown lands to workers' soviets. Faced with the threat of German invasion, he argued that Russia should immediately sign a peace treaty—which led to Russia's exit from the First World War. In 1921 Lenin proposed the New Economic Policy, a system of state capitalism that started the process of industrialisation and recovery from the Russian Civil War. In 1922, the Russian SFSR joined former territories of the Russian Empire in becoming the Soviet Union, with Lenin as its leader. The Bolshevik faction later became the Communist Party of the Soviet Union, which acted as a vanguard party presiding over a single-party dictatorship of the proletariat.
After his death, Marxism–Leninism developed into a variety of schools of thought, namely Stalinism, Trotskyism and Maoism. Lenin remains a controversial and highly divisive world figure. Detractors have labelled him a dictator whose administration oversaw multiple human rights abuses, but supporters have countered this criticism citing the limitations on his power and have promoted him as a champion of the working class. He has had a significant influence on the international Communist movement and was one of the most influential figures of the 20th century.