https://en.wikipedia.org/wiki/Mensheviks
The Mensheviks (Russian: меньшевики́, from меньшинство 'minority') were one of the three dominant factions in the Russian socialist movement, the others being the Bolsheviks and Socialist Revolutionaries.. The factions emerged in 1903 following a dispute within the Russian Social Democratic Labour Party (RSDLP) between Julius Martov and Vladimir Lenin.