It was a coalition between leftist republicans and workers' organizations to defend social reforms of the first government of Second Spanish Republic (1931-1933) and liberate political prisioners from Asturian October Revolution (1934).
The Popular Front defeated the National Front (a collection of right-wing parties) and won the 1936 election, forming the new Spanish Government. Manuel Azaña was elected President of the Republic on May 1936. On July 1936, Francisco Franco and other conservative/monarchist generals instigated a coup d'etat which started the Spanish Civil War (1936-1939). The Government brought weapons to armed groups organized by the unions (UGT and CNT) and workers' parties (PSOE, PCE, POUM) that had intitial success in defeating the fascist forces in Madrid, Barcelona, Bilbao and Valencia. Ultimately though Franco would defeat the Popular Front forces due to the greater aid his forces receieved from abroad, and that the Popular Front forces fragmented and often fought amongst one another. Franco would rule Spain as a dictatorship until he died in 1975.