Anarchism in Spain has historically gained more support and influence than anywhere else, especially before Francisco Franco's victory in the Spanish Civil War of 1936–39.
There were several variants of anarchism in Spain: expropriative anarchism in the period leading up to the conflict, the peasant anarchism in the countryside of Andalusia; urban anarcho-syndicalism in Catalonia, particularly its capital Barcelona; and what is sometimes called "pure" anarchism in other cities such as Zaragoza. However, these were complementary trajectories, and shared a great deal of ideological similarities.
Early on, the success of the anarchist movement was sporadic. Anarchists would organize a strike and ranks would swell. Usually, repression by police reduced the numbers again, but at the same time further radicalized many strikers. This cycle helped lead to an era of mutual violence at the beginning of the 20th century, in which armed anarchists and pistoleros, armed men paid by company owners, were both responsible for political assassinations.
In the 20th century, this violence began to fade, and the movement gained speed with the rise of anarcho-syndicalism and the creation of the huge libertarian trade union, the Confederación Nacional del Trabajo (CNT). General strikes became common, and large portions of the Spanish working class adopted anarchist ideas. There also emerged a small individualist anarchist movement based on publications such as Iniciales and La Revista Blanca. The Federación Anarquista Ibérica (FAI, Iberian Anarchist Federation) was created as a purely anarchist association, with the intention of keeping the CNT focused on the principles of anarchism.