Abu Muhammad Musa ibn Mahdi al-Hadi (Arabic: ??? ???? ???? ?? ?????? ???????) (born: 147 AH (764 AD); died: 170 AH (786 AD)) was the fourth Abbasid caliph who succeeded his father Al-Mahdi and ruled from 169 AH (785 AD) until his death in 170 AH (786 AD).