Fatimid Egypt

During the initial Islamic invasion in 639 AD, Egypt was ruled at first by governors acting in the name of the Righteous Caliphs, and then the Ummayad Caliphs in Damascus but, in 747, the Ummayads were overthrown. In 1174, Egypt came under the rule of Ayyubids that lasted until 1252.

The Ayyubids were overthrown by their bodyguards, known as the Mamluks, who ruled under the suzerainty of Abbasid Caliphs until 1517, when Egypt became part of the Ottoman Empire.

In 639 an army of some 4,000 men were sent against Egypt by the second caliph, Umar, under the command of Amr ibn al-As. This army was joined by another 5,000 men in 640 and defeated a Byzantine army at the battle of Heliopolis. Amr next proceeded in the direction of Alexandria, which was surrendered to him by a treaty signed on November 8, 641. Alexandria was regained for the Byzantine Empire in 645 but was retaken by Amr in 646. In 654 an invasion fleet sent by Constans II was repulsed. From that time no serious effort was made by the Byzantines to regain possession of the country.

Following the first surrender of Alexandria, Amr chose a new site to settle his men, near the location of the Byzantine fortress of Babylon. The new settlement received the name of Fustat, after Amr's tent, which had been pitched there when the Arabs besieged the fortress. Fustat quickly became the focal point of Islamic Egypt, and, with the exception of the brief relocation to Helwan during a plague in 689, and the period of 750–763, when the seat of the governor moved to Askar, the capital and residence of the administration. After the conquest, the country was initially divided in two provinces, Upper Egypt (al-sa'id) and Lower Egypt with the Nile Delta (asfal al-ard). In 643/4, however, Caliph Uthman appointed a single governor (wāli) with jurisdiction over all of Egypt, resident at Fustat. The governor would in turn nominate deputies for Upper and Lower Egypt. Alexandria remained a distinct district, reflecting both its role as the country's shield against Byzantine attacks, and as the major naval base. It was considered a frontier fortress (ribat) under a military governor and was heavily garrisoned, with a quarter of the province's garrison serving there in semi-annual rotation. Next to the wāli, there was also the commander of the police (ṣāḥib al-shurṭa), responsible for internal security and for commanding the jund (army).

...
Wikipedia