After initially being a province of the Umayyad and Abbasid Caliphates, with its administrative capital at Fustat, Egypt became more politically independent in the 9th century under the Tulunid dynasty. In the 10th century, the Fatimid Caliphate moved its base of power to Egypt and founded the city of Cairo, near Fustat. Fatimid architecture in Egypt can be witnessed in religious monuments in Cairo such as the Al-Azhar Mosque (significantly modified in later centuries), the Al-Hakim Mosque, and in the small but artistically significant Aqmar Mosque. Other remains from this period include the monumental stone gates of Cairo – Bab al-Futuh, Bab al-Nasr, and Bab Zuweila – which were built by a Fatimid vizier in the 11th century. The Great Fatimid Palaces, where the caliphs lived, have not been preserved. After the Fatimids, Egypt became the capital of the Ayyubid dynasty founded by Salah ad-Din (Saladin). The most significant monument of this era was the Citadel of Cairo, which became Egypt's center of government up until the 19th century. In the mid-13th century the Mamluks took control and ruled an empire from Cairo that lasted until the Ottoman conquest of 1517. The Mamluks were major patrons of architecture and a large part of the historic heritage of Islamic Cairo dates from their time. The major monuments of Mamluk architecture were multi-functional religious and funerary complexes whose layouts were adapted to fit into the dense urban environment. Some of the most significant examples of this period include the Complex of Sultan Qalawun, the Madrasa-Mosque of Sultan Hasan, and the Funerary complex of Sultan Qaytbay.