The Russian Social Democrats split into Bolsheviks and Mensheviks
A quarrel over party membership at a congress in Brussels and London produces the two factions that will fight for Russia's future.
Quick facts
- Congress location
- Brussels, then London
- Bolshevik
- From bolshinstvo, "majority"
- Menshevik
- From menshinstvo, "minority"
What happened
The Russian Social Democratic Labour Party held its Second Congress in the summer of 1903, meeting first in Brussels and finishing in London because most delegates were living in exile. The split turned on how the party should be organized. Vladimir Lenin argued for a tight, disciplined party of professional revolutionaries; other delegates wanted a broader, more open membership. Lenin's faction won a narrow majority in a vote on party rules, though several delegates had already walked out by then, and took the name Bolsheviks, from bolshinstvo, the Russian word for majority. The losing side became the Mensheviks, from menshinstvo, minority, labels that stuck even after the numerical balance between the two groups shifted over the following years.
Why it matters
The organizational question Lenin won in 1903, a small, disciplined vanguard party versus a mass membership party, gave the Bolsheviks the structure that let them seize and hold power in 1917 while larger, looser socialist parties fractured under pressure. The rivalry between the two factions ran through every socialist argument in Russia for the next 15 years.
How we know
The congress location, the vote on party rules, and the origin of the Bolshevik and Menshevik names are documented in World History Encyclopedia's account, which cites historian Simon Sebag Montefiore's description of Lenin's proposed party of professional revolutionaries.
Sources
- World History Encyclopedia. The Difference Between the Mensheviks & Bolsheviks · Reputable sourceworldhistory.org · The domain "worldhistory.org" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- World History Encyclopedia. The Difference Between the Mensheviks & Bolsheviks · Reputable sourceworldhistory.org · The domain "worldhistory.org" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
See something wrong? . Corrections with a source get fixed fastest.
Part of a timelineThe Russian Revolution29 events · How three centuries of Romanov rule collapsed in a single year, and how the party that caught power in the wreckage never let go.View all →