In 1903, a disagreement regarding membership marked a split within the Russian Social Democratic Labor Party. At the Congress, Martov and Lenin were in disagreement over party membership and centralized control of the party. Lenin had a basic mistrust of workers' instincts and attempted to limit membership to active participants in party organizations. Martov, on the other hand, wanted a more broad-based party that would include both full-time revolutionaries and less active supporters.
While Lenin lost to Martov when the issue of membership was put to a vote, he did win on another important issue. The congress's decision to agree to stronger controls over the RSDLP by a reduced Iskra board signaled victory for Lenin since he and Plekhanov were elected to the board. At the congress Lenin declared his faction to be the bolshinstvo (majority), while those of his rival, Martov, would be the menshinstvo (minority). These two groups have come to be known as the Bolsheviks and the Mensheviks. It was not known at the time that the split, and the subsequent party names, would endure for as long as they did.
There were several fundamental differences between the Bolsheviks and Mensheviks. The Mensheviks wanted to follow a more evolutionary path, as opposed to revolutionary, and did not want to overthrow the current government. They sought to improve the existing conditions. This mostly Proletariat party had some intelligentsia, but was mass based for the most part. Unlike the Bolsheviks, this was truly a party of the Proletariat, not over them. The Mensheviks were much more alligned with the ideology of Marx, in comparison to their opponents.
Both Marx and the Mensheviks recognized the the need for a capitalist revolution in order to achieve socialism. Lenin, however, felt that he could forego this requirement since Russia was neither an industrialized country, nor had she experienced full-blown capitalism, something that Marx said was necessary in order for a revolution to occur. The Mensheviks wanted a Parliamentary Bourgeoise run by capitalists(socialists). This would, however, take quite a while since a long run of capitalism was necessary. Not surprisingly, the Bolsheviks were able to seize power and control.