Socialist rule of the region began with the Spanish Revolution of 1936, resulting in workers' control of businesses and factories, collective farming in the countryside, and attacks against Spanish nationalists and the Catholic clergy. The growing influence of the Communist Party of Spain's (PCE) Popular Front government and their desire to nationalize revolutionary committees and militias brought it into conflict with the CNT and POUM, resulting in the May Days and the eventual replacement of the CNT by the PSUC as the major political force in Catalonia until their defeat to the Nationalist forces in 1939.