The First International
The trade unionists who formed the International Workingmen's Association (IWA), sometimes called the First International, recognised that the working class was an international class which had to link its struggle on an international scale. By joining together across national borders, the workers would gain greater bargaining power and political influence.
Founded in 1864, the IWA was the first mass movement with a specifically international focus. At its peak, the IWA had 5 million members, according to police reports from the various countries in which it had a significant presence. Repression in Europe and internal divisions between the anarchist and Marxist currents led eventually to its dissolution in 1876. Shortly thereafter, the Marxist and revolutionary socialist tendencies continued the internationalist strategy of the IWA through the successor organisation of the Second International, though without the inclusion of the anarchist and anarcho-syndicalist movements.
Read more about this topic: Proletarian Internationalism