Abu Mansur Nizar (Arabic: ??? ????? ?????, romanized: Abu Man?ur Nizar; 10 May 955 – 14 October 996), known by his regnal name as al-Aziz Billah (Arabic: ?????? ??????, romanized: al-?Aziz bi?llah, lit.
'the mighty through God'), was the fifth caliph of the Fatimid dynasty, from 975 to his death in 996.