Abū ʿAlī Manṣūr (13 August 985 – 13 February 1021), better known by his regnal title al-Ḥākim bi-Amr Allāh (Arabic:
الحاكم بأمر الله; 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 whose eponymous founder ad-Darazi proclaimed him as the incarnation of God in 1018.
William of Tyre went so far as to claim that al-Ḥākim's destruction of the Church of the Holy Sepulchre in 1009 was due to his eagerness to disprove taunts that he was a Christian born of a Christian woman.
Around 1009, the year in which Fatimid caliph Al-Hakim bi-Amr Allah ordered the destruction of the Church of the Holy Sepulchre, Christians in Jerusalem hid part of the True Cross and it remained hidden until the city was taken by the European soldiers of the First Crusade.