abstract:Muhammad ibn Mansur al-Mahdi () (born: 126 or 127 AH; died: 169 AH) (born: 744 or 745 AD; died: 785 AD),Al-Souyouti, Tarikh Al-Kholafa'a (The History of Caliphs) was the third Abbasid Caliph who reigned from 158 AH to 169 AH (775–785).Stanley Lane-Poole, The Coins of the Eastern Khaleefahs in the British Museum He succeeded his father, al-Mansur.