The Citadel of Cairo or Citadel of Saladin is a medieval Islamic-era fortification in Cairo, Egypt, built by Salah ad-Din (Saladin) and further developed by subsequent Egyptian rulers. It was the seat of government in Egypt and the residence of its rulers for nearly 700 years from the 13th to the 19th centuries. Its location on a promontory of the Mokattam hills near the center of Cairo commands a strategic position overlooking the city and dominating its skyline. At the time of its construction, it was among the most impressive and ambitious military fortification projects of its time. It is now a preserved historic site, including mosques and museums.