The Aqmar Mosque (), was built in Cairo, Egypt, as a neighborhood mosque by the Fatimid vizier al-Ma'mun al-Bata'ihi in 1125-6 CE (519 Hijri). The mosque is situated on what was once the main avenue and ceremonial heart of Cairo, known today as al-Mu'izz Street, in the immediate neighborhood of the former Fatimid caliphal palaces. The mosque is an important monument of Fatimid architecture and of historic Cairo due to the exceptional decoration of its exterior façade and the innovative design of its floor plan. History The mosque was built by the Fatimid vizier al-Ma'mun al-Bata'ihi, who served in this position from 1121 to 1125 under the Caliph al-Amir. He served during a period of great political and spiritual crisis for the Fatimid Caliphate, not long after the sudden incursion of the First Crusade. He initiated a number of reforms and revived the ceremonial aspects of the caliphate, both at court and in public. He also conducted other constructions and renovations inside the Fatimid Great Palaces. He was arrested shortly after completing the mosque in 1125, and was executed 3 years later.He had grown up in poverty following his father's death and, before being hired by the vizier al-Afdal (his predecessor), he had been working low-status jobs which reportedly included learning building skills. This early experience may have encouraged his later architectural achievements. The al-Aqmar mosque was built at the northeastern corner of the eastern Fatimid Great Palace, and may have served both the neighbourhood and the palace inhabitants. Its adjacency to the palace may have been one reason why it did not feature a minaret; in order to prevent anyone climbing the minaret from looking down into the caliph's palaces. Similarly to Al-Azhar Mosque (970) and the Al-Hakim Mosque (990–1013), formerly named al-Anwar, the name of the al-Aqmar mosque is an epithet of the patron in connection with light. The Mamluk amir Yalbugha al-Salimi restored the mosque in 1393 or 1397 and added a minaret (which collapsed in 1412 and was later restored) as well as shop stalls to the right of the entrance. Al-Salimi also restored or replaced the minbar, the mihrab, and the ablutions area. The mosque was restored again in the 19th century, during the reign of Muhammad 'Ali (r. 1805–1848), by amir Sulayman Agha al-Silahdar, who also built a nearby mosque across the street. In 1993, the mosque was extensively and heavily renovated by the