Georgi Plekhanov in the context of "Second International"

The Bolsheviks, led by Vladimir Lenin, were a radical faction of the Marxist Russian Social Democratic Labour Party (RSDLP) which split with the Mensheviks at the Second Party Congress in 1903. The Bolshevik party, formally established in 1912, seized power in Russia in the October Revolution of 1917 and was later renamed the Russian Communist Party, All-Union Communist Party, and ultimately the Communist Party of the Soviet Union. Its ideology, based on Leninist and later Marxist–Leninist principles, became known as Bolshevism.

The origin of the RSDLP split was Lenin's support for a smaller party of professional revolutionaries, as opposed to the Menshevik desire for a broad party membership. The influence of the factions fluctuated in the years up to 1912, when the RSDLP formally split in two. The political philosophy of the Bolsheviks was based on the Leninist principles of vanguardism and democratic centralism. Lenin was also more willing to use illegal means such as robbery to fund the party's activities. By 1917, influenced by the experiences of World War I, he reached the conclusion that the chain of world capitalism could "break at its weakest link" in Russia before it assumed the level of the advanced countries, opposing theorists such as Georgi Plekhanov. Lenin had also come to view poorer peasants as potential allies of the relatively small Russian proletariat.

The Mensheviks (lit. 'the Minority') were a faction of the Marxist Russian Social Democratic Labour Party (RSDLP) which split with Vladimir Lenin's Bolshevik faction at the Second Party Congress in 1903. Mensheviks held more moderate and reformist views as compared to the Bolsheviks, and were led by figures including Julius Martov and Pavel Axelrod.

The initial point of disagreement was the Mensheviks' support for a broad party membership, as opposed to Lenin's support for a smaller party of professional revolutionaries. The Bolsheviks gained a majority on the Central Committee in 1903, although the power of the two factions fluctuated in the following years. Mensheviks were associated with Georgi Plekhanov's position that a bourgeois-democratic revolution and period of capitalism would need to occur before the conditions for a socialist revolution emerged. Some Mensheviks, notably Alexander Potresov, called for the party to suspend illegal revolutionary work to focus more on trade union work (legal since 1906) and elections to the Duma; this was condemned by Lenin.

Nikolay Gavrilovich Chernyshevsky (24 July [O.S. 12 July] 1828 – 29 October [O.S. 17 October] 1889) was a Russian literary and social critic, journalist, novelist, democrat, and socialist philosopher, often identified as a utopian socialist and leading theoretician of Russian nihilism and the Narodniks. He was the dominant intellectual figure of the 1860s revolutionary democratic movement in Russia, despite spending much of his later life in exile to Siberia, and was later highly praised by Karl Marx, Georgi Plekhanov, and Vladimir Lenin.

Emancipation of Labour (Russian: Освобождение труда) was the first Russian Marxist group. It was founded in exile by Georgi Plekhanov, Vasily Ignatov [ru], Vera Zasulich, Leo Deutsch, and Pavel Axelrod, at Geneva (Switzerland) in 1883. Deutsch left the group in 1884 when he was arrested and sent to Siberia and Sergei Ingerman [ru] joined in 1888. The group published the first Russian language translations of many works by Karl Marx and distributed them. It became the major adversary to the Narodniks on the left wing of politics in the Russian Empire.

Two drafts (1883 and 1885) of a program for the Russian Social Democrats, written by Plekhanov, were also published by the group, marking an important step to what would become the building of the Russian Social Democratic Labour Party (RSDLP). At the first congress of the Second International in Paris (1889) onwards, the group represented the RSDLP.