Abū Manṣūr b. Yūsuf, ʿAbd al-Malik b. Muḥammad b. Yūsuf (395–Muḥarram 460/1005–November 1067), known as al-Shaykh al-Ajall (the most august shaykh), was an influential religious personality of the Ḥanbalī madhhab. As a prominent political figure and advisor to al-Qāʾim, the ʿAbbāsid caliph, he played an important role in events in the middle of the 5th/11th century.

Abū Manṣūr came from one of the notable families of the Baghdad Ḥanbalīs (Massignon, 2/491). All that is known about his education is that he studied ḥadīth with his maternal grandfather, Imām Abū al-Ḥusayn Aḥmad …