Al-Hakim bi-Amr Allah, Fatimid caliph (died 1021)

Abu Ali al-Mansur, better known by his regnal name al-Hakim bi-Amr Allah, was the sixth Fatimid caliph and 16th Ismaili imam (996–1021). Al-Hakim is an important figure in a number of Shia Ismaili sects, such as the world's 15 million Nizaris and 1–2 million Musta'lis, in addition to 2 million Druze.