(born April 22, 1870, Simbirsk, Russia—died Jan. 21, 1924, Gorki, near Moscow) Founder of the Russian Communist Party, leader of the Russian Revolution of 1917, and architect and builder of the Soviet state. Born to a middle-class family, he was strongly influenced by his eldest brother, Aleksandr, who was hanged in 1887 for conspiring to assassinate the tsar. He studied law and became a Marxist in 1889 while practicing law. He was arrested as a subversive in 1895 and exiled to Siberia, where he married Nadezhda Krupskaya. They lived in western Europe after 1900. At the 1903 meeting in London of the Russian Social-Democratic Workers’ Party, he emerged as the leader of the Bolshevik faction. In several revolutionary newspapers that he founded and edited, he put forth his theory of the party as the vanguard of the proletariat, a centralized body organized around a core of professional revolutionaries; his ideas, later known as Leninism, would be joined with Karl Marx’s theories to form Marxism-Leninism, which became the communist worldview. With the outbreak of the Russian Revolution of 1905, he returned to Russia, but he resumed his exile in 1907 and continued his energetic agitation for the next 10 years. He saw World War I as an opportunity to turn a war of nations into a war of classes, and he returned to Russia with the Russian Revolution of 1917 to lead the Bolshevik coup that overthrew the provisional government of Aleksandr Kerensky. As revolutionary leader of the Soviet state, he signed the Treaty of Brest-Litovsk with Germany (1918) and repulsed counterrevolutionary threats in the Russian Civil War. He founded the Comintern in 1919. His policy of War Communism prevailed until 1921, and to forestall economic disaster he launched the New Economic Policy. In ill health from 1922, he died of a stroke in 1924.