The International Brigades (Spanish: Brigadas Internacionales) were military units of foreign communist, socialist and anarchist volunteers that fought on behalf of the Spanish Republic during the Spanish Civil War.
The idea to set them was proposed by the Soviet Union in September 1936 and carried out mostly by French and exiled Italian and German communists operating out of Paris. In order to result more effective the volunteers were divided in battalions according to their nationality. These battalions were then named after some historical figure from that country that was identified as progressive: for example, the battalion of American volunteers was known as the Abraham Lincoln Brigade.
The Internationals, many of them veterans of World War I, were effectively used during the Siege of Madrid and several battles such as Jarama, Guadalajara, Teruel and the Ebro. Their successes soon became a sore point for the Non-Intervention Committee lead by the governments of Britain and France, who demanded their withdrawal while turning a blind eye on the substantial help provided to the Nationalist side by Italy and Nazi Germany. This withdrawal was finally ordeed by the Republican government in 21 September, 1938, hoping that it would be followed by a subsequent withdrawal of Axis forces and the lift of the arms embargo on the Republic by the western powers. However, none of these happened, and Britain and France immediately capitulated to Hitler's ambitions in the Munich Conference about a week later.
International Brigades in The War That Came Early
The International Brigades were deployed to the Ebro front when a Second World War broke out in October 1938. France, who had been withholding the transit of military equipment to the Republic for most of the war, suddenly changed her policy allowing the Republican forces to reconquer Vinaroz and beat back the latest Nationalist drive to the Mediterranean. The expected withdrawal of the International Brigades was also called off.
After war in the Ebro froze solid in the winter of 1938, the Internationals were redeployed to Madrid in anticipation of a renewed Nationalist offensive. After months of fierce fighting they managed to expel the Nationalists from the ruins of the University City, the only district of the Spanish capital that they had managed to occupy.