Feuds between rival candidates to the regency and commercial conflicts between Venice and Genoa, resulted in a new civil war in 1256 known as the War of Saint Sabas. The pro-Venetian Bohemond VI's conflict with his Genoese vassals the Embriaci brought the war to Tripoli and Antioch. In 1258, the Hulagu, younger brother of the Great Khan Möngke, sacked Baghdad and ended the Abbasid Caliphate. Two years later, Hethum I of Cilicia and Bohemond VI joined forces with the Mongols in the sack of Aleppo, when Bohemond set fire to its mosque, and in the conquest of northern Syria. The Mongols emancipated the Christians from their status, and the local Christian population cooperated with the conquerors. Jerusalem remained neutral when the Mamluks of Egypt moved to confront the Mongols after Hulagu, and much of his force moved east on the death of Möngke to address the Mongol succession. The Mamluks defeated the greatly reduced Mongol army at Ain Jalut. On their return, the Mamluk sultan Qutuz was assassinated and replaced by the general Baibars. Baibars revived Saladin's empire by uniting Egypt and Syria and held Hulagu in check through an alliance with the Mongols of the Golden Horde. He reformed governance in Egypt, giving power to the elite . The Franks did not have the military capability to resist this new threat. A Mongol garrison was stationed at Antioch, and individual Frankish barons concluded separate truces with Baibars. He was determined to conquer the crusader states. He captured Caesarea and Arsuf in 1265 and Safed in 1266, and sacked Antioch in 1268. Jaffa surrendered and Baibers weakened the military orders by capturing the castles of Krak des Chevaliers and Montfort before returning his attention to the Mongols of the Ilkhanate for the rest of his life. Massacres of the Franks and native Christians regularly followed a Mamluk conquest.