Abū Yaḥyā Zakariyyāʾ ibn al-Wāthiq, better known by his regnal name al-Mustaʿṣim bi-'llāh, was the eighth Abbasid caliph of Cairo under the tutelage of the Mamluk Sultanate. He was installed as caliph briefly in 1377, and then again from 1386 to 1389.
- Occupation
- politician
- Position held
- Abbasid caliph
- Died
- 1389
