Sold into slavery in Egypt, he rose to vice-Sultan over 20 years, becoming the power behind the throne. He was prominent in defeating the Seventh Crusade, which invaded Egypt in 1249–50. When Egypt was threatened by the Mongols in 1259 he took the lead militarily and then deposed the reigning Sultan, 15-year-old Sultan Al-Mansur Ali. The centers of Islamic power in Syria and Baghdad were conquered by the Mongols, and the center of the Islamic Empire transferred to Egypt, which became their next target. Qutuz led an Egyptian Mamluk army north to confront the Mongols, having made a pact with Egypt's long-time enemy the Crusaders.