Social Democratic Party (Netherlands)

In 1907 tensions arose within the Social Democratic Workers' Party (SDAP) between revolutionary Marxists grouped around De Tribune (The Tribune) and the leadership of the SDAP, who were more oriented towards more a revisionist ideology and a parliamentary and reformist political strategy.

As Jan Ceton, Willem van Ravesteyn and David Wijnkoop and other participants in De Tribune increasingly criticized the leadership of the SDAP.

Wijnkoop and Ceton refused and they and their supporters, including the poet Herman Gorter and the mathematician Gerrit Mannoury, left to form a breakaway party.

[1] They had a membership of around 400 spread across different cities: Amsterdam (160), Rotterdam (65), The Hague (45), Leiden (56), Utrecht (25), Bussum (15).

The mobilization for the First World War, which the SDAP supported and the SDP opposed, further strengthened the differences between the parties.

Congress of the SDP, Afdeling Rotterdam, 1911. From Left to right: Sam de Wolff, Willem van Ravesteyn , Herman Gorter , David Wijnkoop , Louis de Visser , Gerrit Mannoury and Jan Ceton