The Mensheviks and the Bolsheviks were two revolutionary factions that emerged after 1904, and particularly after the largely failed Russian Revolution of 1905. The split in the Social-Democratic Labour Party had its origins in a disagreement between Vladimir Lenin, who came to be identified with the Bolsheviks, and Julius Martov. Both parties were, fundamentally, revolutionary socialists, but over time the Mensheviks took more moderate positions, particularly aligning themselves with various reform-minded liberal groups. The Bolsheviks, on the other hand, preferred to align with radical peasant and workers' organizations. After the 1917 revolution and the establishment of a heavily Menshevik provisional government, the primary issue dividing the two factions was whether or not Russia should remove itself from World War I. The Mensheviks lost out in the Bolshevik Revolution, and were driven from power and in many cases killed or imprisoned during the Russian Civil War.