After the fall of Jerusalem, a combined force was assembled, consisting of Templars, the Hospitallers and Teutonic Knights, joining a Muslim army of Syrians and Transjordanians under al-Mansur Ibrahim and an-Nasir Dā’ūd. This army was placed under the command of Walter IV of Brienne and left Acre, now the headquarters of the Order, and departed on 4 October 1244. They fell on the Khwarezmians and the Egyptian troops commanded by Baibars, future Mamluk sultan of Egypt, on 17 October. In the Battle of La Forbie near Gaza, the Muslim allies of the Franks dropped out at the first encounter with the enemy and the Christians found themselves alone. The unequal fighting ended in disaster––16,000 men lost their lives and 800 were taken prisoner, among them 325 knights and 200 turcopoliers of the Hospitallers. Guillaume de Chateauneuf himself was captured and taken to Cairo. Only 18 Templars and 16 Hospitallers managed to escape. The resulting Ayyubid victory led to the call for the Seventh Crusade and marked the collapse of Christian power in the Holy Land.