Foreign Intervention: Germany, Italy, the Soviet Union, and Non-Intervention

From the earliest days of the uprising, Franco sought military aid from Hitler and Mussolini. Germany sent Junkers transport planes to ferry the Army of Africa and created the Condor Legion, an air and technical support force for the Francoist side, while Italy sent the Corpo Truppe Volontarie, numbering tens of thousands of soldiers. Both powers used the Spanish war as a testing ground for weapons and tactics, most infamously in the bombing of Guernica by the Condor Legion and Italian aviation on 26 April 1937, an attack with enormous international repercussions immortalized in Pablo Picasso's painting. Germany and Italy supplied the Francoist side with weapons, tanks, and artillery on a massive scale and extended early diplomatic recognition to Franco's government in November 1936, strengthening the emerging Rome-Berlin Axis even though Italy suffered a notable setback with its defeat at the Battle of Guadalajara in March 1937.