 A fundamental change occurred when the Fatimid Caliphate attempted to push into Syria in the latter half of the 10th century.The Fatimids were faced with the now Turkish-dominated forces of the Abbasid Caliphate and began to realize the limits of their current military.Thus during the reign of Abu Mansur Nizar al-Aziz Billah and Al-Hakim bi-Amr Allah, the Caliph began incorporating armies of Turks and, later, black Africans (even later, other groups such as Armenians were also used).