Politics in the 13th-century eastern Mediterranean were complex, with numerous powerful and interested parties. The French were led by the very devout Louis IX of France and his ambitiously expansionist brother Charles I of Naples. Communication with the Mongols was hindered by the enormous distances involved. Louis sent an embassy to the Mongols in Iran in 1249 seeking a Franco-Mongol alliance. When the reply found him in Palestine in 1251 it was again only a demand for tribute. Louis organised a new crusade, called the Seventh Crusade, to attack Egypt, arriving in 1249. He was defeated at Mansura and captured as he retreated to Damietta. Another ten-year truce was agreed. Louis and his nobles were ransomed while the other prisoners were given a choice between conversion to Islam or beheading. He remained in Syria until 1254 to consolidate the crusader states. A brutal power struggle developed in Egypt between various Mamluk leaders and the remaining weak Ayyubid rulers. The Mamluks were slave soldiers that had been used by Muslim rulers for centuries. Most of them were Turks from the Eurasian Steppe or Christians from Anatolia; kidnapped as boys, converted to Islam and given military training. The threat presented by an invasion by the Mongols led to Qutuz seizing the sultanate in 1259 and uniting with another faction led by Baibars to defeat the Mongols at Ain Jalut. The Mamluks then quickly gained control of Damascus and Aleppo before Qutuz was assassinated, most probably by Baibers.