The Sixth Party Conference held in Prague in January 1912 was a watershed in the history of the Russian Social Democratic Labour Party (RSDRP). Prior to this gathering, many party members had hoped that divisive factionalism, which had begun with the Menshevik-Bolshevik split at the Second Congress in 1903, could be cured, and that the two groups could exploit in concert the growing worker unrest in Russia. Social Democrats, particularly rank and file members in the underground, were encouraged by the results of the ‘Unification’ Congress held in Stockholm in 1906 and the ‘Unification’ Plenum of the Central Committee which met in Paris in January 1910. In each instance, the émigré leaders were forced to acknowledge the principle of party unity and to agree to work within common leadership bodies. But in 1912 this façade of unity collapsed. The two factions met separately that year – the Bolsheviks in Prague during January, the Mensheviks in Vienna during August – and the outcome was in effect the creation of two separate Social Democratic parties, each with its own leadership bodies, programme and contacts with the underground. Never again would the two factions meet together. From 1912 to 1917, instead of working in concert for the overthrow of the autocracy, they were in competition for worker support. The ultimate winner of the contest was V. I. Lenin and his Bolshevik Party. Many of the reasons for his triumph can be found in the manner in which he called the Prague Conference, the resolutions which it passed, and the reorganization which it achieved.