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The full name of al-Hadi is Abū Muḥammad Mūsā ibn al-Mahdī al-Hādī. He was the third caliph of the Abbasid Caliphate, ruling from 785 to 786. He succeeded his father, al-Mahdi, and was in turn succeeded by his brother, Harun al-Rashid. Al-Hadi's reign was relatively short and marked by internal conflicts and rebellions, including a failed coup attempt by his uncle, Isa ibn Musa.