Vladimir Ilyich Ulyanov was a Russian revolutionary, politician, and political theorist, best known by his pseudonym Lenin. From 1917 to 1924, he served as head of government for Soviet Russia and from 1922 to 1924 for the Soviet Union.
After the death of Lenin, Stalin emerged as the leader of the communist party.
A power struggle existed for a brief period after Lenin's death in 1924. Through banning all political parties, Stalin then came to power. He developed Marxism-Leninism then.
Russia, and later the Soviet Union, became a one-party Marxist-Leninist state under his rule, ruled by the Soviet Union's Communist Party. He formed a version of it known as Leninism, ideologically a Marxist.
Born in Simbirsk to a moderately affluent middle-class family, Lenin supported revolutionary socialist politics following the 1887 execution of his brother. In 1893, he settled in Saint Petersburg and became a senior Marxist activist. He called for the First World War to be turned into a proletarian revolution throughout Europe after Russia's failed Revolution of 1905, which as a Marxist, he claimed would trigger the downfall of capitalism and its reaction to socialism.
Joseph Vissarionovich Stalin was a revolutionary and Soviet Georgian politician who ruled from the mid-1920s until his death in 1953 in the Soviet Union. He served both as general secretary of the Communist Party of the Soviet Union (1922-1952) and as chairman of the Council of Ministers of the Soviet Union (1941-1953) during his years in power.
Stalin eventually centralised power to become the de facto ruler of the Soviet Union in the 1930s, despite initially ruling the country as part of a joint leadership. These theories were formalised as Marxism-Leninism by Stalin, a communist ideologically committed to the Leninist understanding of Marxism, although his own policies are known as Stalinism.