Abū ʿAlī Manṣūr (13 August 985 – 13 February 1021), better known by his regnal name al-Ḥākim bi-Amr Allāh; literally "The Ruler by the Order of God", was the sixth Fatimid caliph and 16th Ismaili imam (996–1021). Al-Hakim is an important figure in a number of Shia Ismaili religions, such as the world's 15 million Nizaris, in addition to the 2 million Druze of the Levant. Source