officially International Working Men's Association
Federation of workers' groups, founded in 1864 by British and French trade-union leaders.
Its structure was highly centralized, based on local groups that were integrated into national federations. It was split by conflicting schools of socialist thought, including those of Karl Marx , Pierre-Joseph Proudhon , Louis-Auguste Blanqui , and Mikhail Bakunin . A clash between Marx's centralized socialism and Bakunin's anarchism in 1872 caused the International to split, and it was dissolved in 1876. Though it was feared at the time as a formidable power with millions of members, and several countries tried to have it outlawed, its membership was never more than 20,000 and it served mainly as a unifying force for labour in Europe.