The Catalan working class movement was quick to join the international trends of the time. In 1869, the Federal Centre of Workers' Societies affiliated to the First International. The First Spanish Workers' Congress was held in Barcelona in June 1870. Of the 98 delegates who attended, 74 were Catalan. At the congress, the Bakuninists triumphed over the Marxists. The dominance of libertarianism led to workers' organisations formally separating themselves from political associations. During the First Republic, leaders of the International Working Men's Association came to an understanding with the federal republicans and their collaboration continued until well into the 20th century.