In 1931, King Alfonso XIII approved elections to decide the government of Spain, and voters overwhelmingly chose to abolish the monarchy in favor of a liberal republic. Alfonso subsequently went into exile, and the Second Republic, initially dominated by middle-class liberals and moderate socialists, was proclaimed. During the first five years of the republic, organized labor and leftist radicals forced widespread liberal reforms as independence-minded Spanish regions such as Catalonia and the Basque provinces achieved virtual autonomy. The landed aristocracy, the church, and a large military clique increasingly employed violence in their opposition to the Second Republic, and in July 1936, General Francisco Franco led a right-wing army revolt in Morocco, which prompted the division of Spain into two key camps: the Nationalists and the Republicans.
Franco’s Nationalist forces rapidly overran much of the Republican-controlled areas in central and northern Spain, and Catalonia became a key Republican stronghold. During 1937, Franco unified the Nationalist forces under the command of the Falange, Spain’s fascist party, while the Republicans fell under the sway of the communists. Germany and Italy aided Franco with an abundance of planes, tanks, and arms, while the Soviet Union aided the Republican side. In addition, small numbers of communists and other radicals from France, the USSR, America, and elsewhere formed the International Brigades to aid the Republican cause. The most significant contribution of these foreign units was the successful defense of Madrid until the end of the war.
In June 1938, the Nationalists drove to the Mediterranean Sea and cut the Republicans’ territory in two. Later in the year, Franco mounted a major offensive against Catalonia. In January 1939, its capital, Barcelona, was captured, and soon after the rest of Catalonia fell. With their cause all but lost, the Republicans attempted to negotiate a peace, but Franco refused. On March 28, 1939, the victorious Nationalists entered Madrid, and the bloody Spanish Civil War came to an end. Up to a million lives were lost in the conflict, the most devastating in Spanish history.