The Battle of Sierra Elvira, also called the Disaster of the Vega de Granada, was a battle of the Spanish Reconquista fought near the city of Granada on 25 June 1319 (6 Jumada al-Awwal 719 AH). The battle was fought between the troops of the Emirate of Granada and those of the Kingdom of Castile. The battle resulted in a catastrophic defeat for Castile. Historical Context The Kingdom of Castile periodically conducted raids into the Emirate of Granada in order to collect plunder. Notwithstanding temporary agreements and truces with the Nasrid rulers, these expeditions were often under the leadership of the rulers of Castile. They were often true military expeditions with large armies numbering thousands of men. In the late 1310s Castile was ruled by King Alfonso XI, a minor, under the joint regency of his grandmother Maria de Molina, of his granduncle infante John and of his uncle infante Peter. Infante Peter had led minor raids into Granadine territory in 1316 and 1317 and an agreement had been reached with the nobility of Castile in the Cortes held at Medina del Campo in 1318 for a new expedition to begin in the late spring of 1319. This expedition was to be a large one, blessed by Pope John XXII who authorized it as a crusade and conceded the rebate to the crown of some of the Church tithes in order to finance it. The troops assembled in Cordoba in June 1319 and crossed the border under the command of infante Peter. With him were the Grand Masters of the Orders of Santiago, Calatrava and Alcántara and the Archbishops of Toledo and Seville. Infante John followed with his own troops. The two infantes resolved to march deep into Granada and to reach the Vega de Granada, the area surrounding the city characterized by its wealth and fertility. During the march the army skirmished with Moorish troops and captured several towns, collecting large amounts of plunder. The battle The large Castilian army encamped in the Vega de Granada and, after looting the immediate area, resolved to return to Castile satisfied with the collected booty. A siege of the city of Granada was deemed impossible at the time. The withdrawal started on 25 June 1319, in very hot weather; infante Peter led the vanguard while infante John commanded the rearguard. At this point Sultan Ismail decided to strike. A large force of