Abu Mansoor Nizar al-Aziz Billah

Al-Aziz (955–996) ( _ar. العزيز بالله) was the fifth Caliph of the Fatimids (975–996).

Since Abdallah, the heir to the throne, had died before his father Ma'ad al-Muizz Li-Deenillah (953-975), his brother Abu l-Mansur Nizar al-Aziz acceded to the Caliphate with the help of Jawhar as-Siqilli. Under Al-Aziz the Fatimid Empire stretched as far as Palestine and Syria (from 977/978). Mecca and Medina also acknowledged the suzerainty of the Fatimids.

The reign of Al-Aziz was primarily significant for the strengthening of Fatimid power in Egypt and Syria, which had then only very recently been conquered (969) - the bedouin Tayyi' tribe was defeated in Palestine 982 and finally subjugated at Damascus 983. Towards the end of his reign Al-Aziz sought to extend his power to northern Syria, focusing his attention on the Hamdanids of Aleppo. The fact that they were under the suzerainty of the Byzantine Empire resulted in the outbreak of war with this great power, a conflict which would not be resolved until the reign of al-Hakim (996-1021).

Another notable development during al-Aziz's reign was the introduction of foreign slave armies. When the Berber troops from the Maghreb continued to be successful in the wars against the Carmathians in Syria, Al-Aziz began setting up units comprised of Turkish slave soldiers, or Mamelukes.

Through the expansion of the bureaucracy (in which many Jews and Christians acquired important posts) the foundations were laid for the immense power of the succeeding Caliphs. His appointment of a Jewish governor over Syria, however, led to grumbling by his Muslim subjects, who claimed they were being pushed out of important posts. As a result, Al-Aziz ordered his Christian and Jewish officials to employ more Muslims in their offices.

The Egyptian economy was also nurtured, and tax revenue thereby increased, through the expansion of streets and canals and the establishment of a stable currency. The general economic well-being was also apparent in an elaborate building programme.

The reign of Al-Aziz was also culturally significant. His grand Vizir Yaqub ibn Killis (979-991) founded the al-Azhar University in Cairo (988) which went on to become the most important centre of learning in the Islamic world. Likewise a library with 200,000 volumes was built in Cairo.

Al-Aziz died on 13 October 996. His son Al-Hakim bi-Amr Allah (996-1021) succeeded him as Caliph.