Rossiĭskai︠a︡ sot︠s︡ial-demokraticheskai︠a︡ rabochai︠a︡ partii︠a︡ (bolʹshevikov)

The Russian Social Democratic Labour Party (RSDLP), also known as the Russian Social Democratic Workers' Party (RSDWP) or the Russian Social Democratic Party (RSDP), was a socialist political party founded in 1898 in Minsk, Russian Empire. The party emerged from the merger of various Marxist groups operating under Tsarist repression, and was dedicated to the overthrow of the autocracy and the establishment of a socialist state based on the revolutionary leadership of the Russian proletariat. The RSDLP's formative years were marked by ideological and strategic disputes culminating at its Second Congress in 1903, where the party split into two main factions: the Bolsheviks, led by Vladimir Lenin, who advocated a tightly organized vanguard of professional revolutionaries; and the Mensheviks, led by Julius Martov and others, who favored a more moderate, broad-based model. During and in the years after the 1905 Revolution, the RSDLP operated both legally and underground, publishing newspapers, infiltrating trade unions, and agitating among industrial workers. Despite repeated attempts at reunification, the rift between the Bolsheviks and Mensheviks widened, resulting in a formal split in 1912. The February Revolution of 1917 saw some Mensheviks support cooperation with the Provisional Government, which the Bolsheviks opposed in favor of "all power to the soviets". After the Bolsheviks seized power in the October Revolution later that year, the RSDLP was effectively dissolved. In 1918, the Bolshevik party formally renamed itself the Russian Communist Party (Bolsheviks), which later became the Communist Party of the Soviet Union.