The Citadel, Cairo, Egypt. In the 12th century, Saladin and his successors built an impenetrable bastion in the Citadel, using the most advanced construction techniques of the age. For the next 700 years, Egypt was ruled from this hill. During the 1330s al-Nasir Muhammad, (who ruled on three different occasions for a total of 42 years - AD 1293-1340) who was considered the greatest Mamluk sultan, tore down most of the Ayyubid buildings to make room for his own needs, which included several palaces and a mosque in addition to barracks for his army. These, too, were not to last, for when the Ottoman Muhammad Ali assumed power in the 1800s he had all the Mamluk buildings razed and the complex entirely rebuilt; only the green-domed mosque and a fragment of al-Qasr al-Ablaq (the striped palace) remain. The Citadel's appearance today is the vision of Muhammad Ali, particularly the mosque that bears his name.