The Mosque of Muhammad Ali stands within the walls of the Citadel in Cairo. Built between 1830 and 1857, it is the largest and grandest of the four mosques contained in the Citadel. Muhammad Ali led a resurgence of national strength which put much of Arabia in Egyptian hands and almost led to the toppling of the Ottoman Empire. However, the momentum of his conquests and his modernization efforts was not sustained by his successors after his death in 1849.