Spanish Civil War, 1936–39, a conflict between the liberal government of the Second Spanish Republic and right-wing rebel forces. It ended with the overthrow of the Second Republic and the establishment of a military dictatorship under General Francisco Franco, leader of the rebels. The war was marked by fierce and bloody fighting and atrocities that included the first large-scale bombings of civilians by airplanes. Estimates of the number of persons killed in the war, including civilians, range from 400,000 to 1,000,000.
The Republic was aided by the Soviet Union and by International Brigades that consisted of thousands of volunteers from various countries, including the United States. The rebels were supported by Nazi Germany and Fascist Italy. Intervention by the three European powers and their use of the war as a testing ground for new weapons later led historians to describe the conflict as “a rehearsal for World War II.”
The government and the factions loyal to it, including Communists, socialists, anarchists, and other left-wing groups, were called Loyalists. The rebels, including Falangists (Spanish fascists), monarchists, and other right-wing factions, were known as Nationalists. The rebels also had the support of the Roman Catholic Church.
After the establishment of the Second Republic in 1931, Spain was engulfed by political and social turmoil. Conservatives opposed the Republican government's liberal programs, and violence broke out between left-wing and right-wing extremists. Conservative military officers particularly were alienated by the government's failure to maintain order and by its anti-Catholic policy. Most of the army generals saw themselves as defenders of Catholic Spain against Communism. When the parliamentary elections of 1936 resulted in a decisive victory for the left-wing parties, the generals decided to revolt.
The civil war began on July 17, 1936, with a seizure of power by insurgent army officers in Spanish Morocco. The rebellion quickly spread to Spain itself, where the clergy, nobility, and most of the army supported it. General Franco assumed command of the rebel forces. The Nationalists soon gained control of most of northern and part of western Spain and established headquarters at Burgos. Aided by large shipments of arms, aircraft, and men from Germany and Italy, rebel forces gradually gained superiority. (Italy at one point had 50,000 troops in Spain.)
The Loyalists suffered throughout the war from a lack of arms and other equipment. Aid from the Soviet Union was sporadic and diminished considerably toward the end of the war. In addition, the British-French policy of nonintervention and the United States arms embargo against Spain made it increasingly difficult for the Loyalists to obtain weapons. There were about 40,000 volunteers in the International Brigades, but they were largely undisciplined and often were used ineffectively.
Throughout 1937 and 1938, the Nationalists steadily pushed the Loyalists eastward. In April, 1938, the rebels reached the coast, cutting Loyalist territory in two. In January, 1939, Franco's troops captured Barcelona, ending effective resistance in the northeast. Loyalist armies in the south soon began to collapse, and the civil war ended in March with the surrender of Madrid and Valencia.
Pablo Picasso's painting Guernica, considered his masterpiece, depicts the horrors of the war. Literary works inspired by the war include Ernest Hemingway's For Whom the Bell Tolls, a novel; and George Orwell's Homage to Catalonia, a nonfiction account of the war.