As soon as the Fatimid dynasty took over ruling Egypt, in 908 AD, the new rulers of Egypt needed to show how important and strong they were. One way of showing that was to build impressive new buildings like the Al-Azhar Mosque in their new capital, Cairo. The Fatimid rulers named it Al-Azhar Mosque after Fatima Al-Azhar, the daughter of the Prophet Mohammed, the woman the Fatimid dynasty is named after.
After that, the Caliphs al-Aziz and his son al-Hakim built a mosque (990-1013 AD). This mosque follows generally the same pattern as the earlier mosque, with a big courtyard and a prayer hall with pointed arches. Three small domes emphasize which side the prayer hall is on. On the opposite side, there’s a big entrance gate. It may be entrance gates like this that gave European architects the idea for Romanesque doorways like that of the Abbaye aux Dames in Caen (1050 AD). Like the Romanesque and later Gothic doorways, the door of Al-Hakim Mosque is in three parts, although here only the middle part actually has a door in it.
The Fatimids also built a great wall around Cairo, with several impressive stone gates in it. These towers and gates, built in 1087 AD, are very similar to the castles that William the Conqueror built in Caen (his home in Normandy) about 1050 AD and in London after he had conquered England in 1066 AD.