The differences between the Bolsheviks and the Mensheviks derived from different opinions on the role of the party and the nature of revolution. The Bolsheviks believed in a highly centralized party of professional revolutionaries, while the Mensheviks believed in a more democratic party structure that allowed disagreements. The Mensheviks were also willing to work with the middle class for their revolutionary ends, while the Bolsheviks were not.
The initial split between the two parties occurred in 1903 when factions led by L. Martov and Vladimir Lenin disputed over who could be a member of the Russian Social-Democratic Labor Party. After a dispute over unrelated issues, a large number of L. Martov's faction left the gathering, allowing Lenin's group to achieve a majority on the party's central committee. This victory is the origin of the two parties' names, as "Bolshevik" means "a member of the majority" and "Menshevik" means "a member of the minority." The Mensheviks, however, drew more public support than the Bolsheviks because of their more inclusive ideals.
The Mensheviks also were inclusive in their approach to other political parties. Though the Bolshevik's scorned other ideologies, many Mensheviks followed the Marxist belief that societies had to have a capitalist system before they could have an effective communist one. As Russia was still pre-capitalist in many ways, Mensheviks were willing to work with conservative and liberal parties to effect a democratic, capitalist system that could become a communist one in the future. The Bolsheviks, however, believed that Russia could go directly from an absolute monarchy to a communist society.