Francisco Largo Caballero was a Spanish politician and trade unionist, who served as the Prime Minister of the Second Spanish Republic during the Spanish Civil War. He was one of the historic leaders of the Spanish Socialist Workers' Party (PSOE) and of the Workers' General Union (UGT). Although he entered into politics as a moderate leftist, he took a more radical turn after the 1933 general election in which the conservative CEDA party won the majority and began to advocate for a socialist revolution.

The Spanish Republic, commonly known as the Second Spanish Republic, was the form of government in Spain from 1931 to 1939. The Republic was proclaimed on 14 April 1931 after the deposition of King Alfonso XIII. It was dissolved on 1 April 1939 after surrendering in the Spanish Civil War to the Nationalists led by General Francisco Franco.