When the Mongols invaded Syria and threatened Damascus after conquering Aleppo in 1260, An-Nasir fled from Damascus, leaving the city virtually undefended. The notables of Damascus started negotiations with the Mongol ruler Hulagu Khan; the city was handed over to his general Kitbuqa in 1260. When the Mongol army left Damascus to quell rebellions in the countryside, the Ayyubid garrison of the citadel revolted, as they had been instructed to do by An-Nasir. In response, the Mongols besieged the citadel in 1260. The garrison surrendered after heavy bombardments and without hope of being relieved by An-Nasir. The defences of the citadel were then largely dismantled.