MIA: Encyclopedia of Marxism: Glossary of Organisations
Founded on Lenin's initiative at the International Socialist Conference held in Zimmerwald in September 1915. It consisted of delegates from the Central Committee of the R.S.D.L.P., the Left Social-Democrats of Sweden, Norway, Switzerland and Germany, the Polish Social-Democratic opposition and the Social-Democrats of the Latvian area.
Led by Lenin, the Zimmerwald Left group waged a struggle against the Centrist majority of the Conference and moved resolutions condemning the First World War, exposing the betrayal by the social-chauvinists, and urging the necessity of active struggle against the war. These draft resolutions were rejected by the Centrist majority.
The Zimmerwald Left succeeded, however, in getting a number of important points from its own draft resolution included in the manifesto adopted by the Conference. Regarding this manifesto as a first step in the fight against the war, the Zimmerwald Left voted for it. The Zimmerwald left issued a special statement detailing the inadequacy and inconsistency of the manifesto and their reasons for voting for it. They declared that while remaining within the Zimmerwald organisation they would disseminate their views and work independently on an international scale. The group elected an executive body – Lenin, Zinoviev and Radek. The Zimmerwald Left published a journal Vorbote (Herald) in German, which carried a number of articles by Lenin.
The Bolsheviks were the guiding force in the Zimmerwald Left. The Zimmerwald Left soon became the rallying point for internationalist elements of world Social-Democracy. The Social-Democrats of various countries who belonged to the Ziminerwald Left group carried on active revolutionary work and played an important role in the establishment of Communist parties in their countries.