Alfonso IV
The deposition of Alfonso Fróilaz precipitated a civil war. Sancho took control of León and was challenged by his brother Alfonso IV, who was assisted by his father-in-law, King Sancho I of Pamplona (died December 925). Alfonso IV was defeated in battle and fled to Astorga in the Asturias, where he made an alliance with Alfonso Fróilaz, who had been forced out of the capital but not the kingdom. The alliance defeated Sancho and forced him to flee to Galicia, leaving Alfonso IV in control of León. The brothers had made peace by 927, with Sancho continuing to rule in Galicia.