On Friday, the 18th of Rabiʿ II. 359, the Kaʾid Jawhar himself presided at the public prayers and sermon in the Old Mosque, that is the Mosque of ʿAmr. The building then existing had been erected by ʿAbdullah b. Tahir in 212, and is still standing. It escaped destruction when the city was burned, but suffered a disastrous restoration in A.D. 1798. At this service many soldiers were present. The preacher was ʿAbdu s-Sami b. Umar al-ʿAbbasi, who in the _khutba_ made especial mention of the “people of the house,” _i.e._, the family of ʿAli, and prayed for the Kaʾid, although Jawhar did not approve of his own name being thus mentioned, saying that no authority for it had been given in the instructions he had received from al-Moʿizz. In the call to prayer the Shiʿite custom of adding the words “come to the excellent work” was adopted. In the month of Jumada I. this addition was made in the call to prayer at the Old Mosque, at which Jawhar was greatly pleased, and made a report of the circumstance to the Khalif (Ibn Khall. i. 344-5). Meanwhile progress was being made with the building of al-Kahira. The new city was surrounded with a wall of large bricks, of which the last fragments were observed by Maqrizi in A.D. 1400. In the middle of the great enclosure was an open space, the _Bayn al-Kasrayn_, “between the two palaces,” as it was afterwards called, large enough for 10,000 troops to be paraded: a small portion of this open space remains as the Suq an-Nahhasin. On the east was the Khalif’s palace; one corner of its site is now marked by the Khan al-Khalili, another by the Husayn Mosque. The name of the square was of later date, and due to the fact that al-Moʿizz’s successor built a lesser palace on its west side, at the beginning of the beautiful garden which Kafur had laid out, and which the Fatimid Khalifs maintained. A great thoroughfare led through the midst of Kahira from the Bab al-Zuwayla on the south side, communicating with the old city of Fustat, and passing through the Bayn al-Kasrayn to the Bab al-Futah, which led out to the open country on the north. To the north of the Khalif’s palace lay the Wazir’s official residence, and to the south the mosque of al-ʾAzhar, which Jawhar commenced soon after the foundation of Kahira and finished on the 7th of Ramadan, 361. Although the existing building has been much modernised it retains enough of the older structure to show the typical character of Fatimid architecture. The horse shoe arch, commonly regarded as of Persian origin, seems to have been developed in Egypt, and appears first in the Nilometer and then in the mosque of Ibn Tulun: it had an Indian parentage, and was not introduced into Persia until it had already been employed in Egypt (Rivoira: _Moslem Architecture_, E.T. 154, etc.), at least no dated example is found until later than the mosque of al-ʾAzhar. The Fatimid style shows this horse-shoe arch combined with high imposts which occur