 While various mamluk factions competed for control of Egypt and Syria, the Mongols under the command of Hulagu Khan had sacked Baghdad, the intellectual and spiritual center of the Islamic world, in 1258, and proceeded westward, capturing Aleppo and Damascus.Qutuz sent military reinforcements to his erstwhile enemy an-Nasir Yusuf in Syria, and reconciled with the Bahriyyah, including Baybars, who was allowed to return to Egypt, to face the common Mongol threat.Hulagu sent emissaries to Qutuz in Cairo, demanding submission to Mongol rule.