ORGANIZER  
In St Petersburg, Lenin joined the growing Marxist circle, and in 1895 he helped create the St Petersburg Union for the Struggle for the Emancipation of the Working Class. Police soon arrested the leaders of this organization. After 15 months in jail, along with another union member, Nadezhda Krupskaya—soon to become his wife—Lenin went into Siberian exile until 1900. At the end of his first period in Siberia Lenin went abroad, where he joined Georgy Plekhanov, L. Martov, and other Marxists in creating a newspaper, Iskra (The Spark). The paper proved to be an effective device in uniting the existing Social-Democrats and inspiring new recruits. In exile Lenin wrote his masterpiece of organizational theory, What Is to Be Done? (1902). His plans for revolution centred on a highly disciplined party of professional revolutionaries, who would serve as the "vanguard of the proletariat" and lead the working masses to an inevitable victory over tsarist absolutism.

Lenin's insistence on the centrality of professional revolutionaries caused a split within the Russian Social Democratic Labour party; at its second congress (1903) it broke apart. Lenin's faction emerged with a small majority of the congress, hence the name Bolshevik (from the Russian word for majority); the opposition became known as Mensheviks (from the Russian word for minority). Quarrels between the two factions dominated party politics until World War I.