Abū al-ʿAbbās al-Sayyārī, al-Qāsim b. al-Qāsim (262–342 /876–953), was a well-known gnostic, theologian and traditionist from Marw. His maternal grandfather was Abū al-Ḥasan Aḥmad b. Sayyār, who was himself a prominent theologian and traditionist, and for this reason Abū al-ʿAbbās became known as al-Sayyārī (Ibn Mākūlā, 4/509; al-Samʿānī, 7/329; Ibn al-Athīr, 2/162). His family consisted of scholars and administrators (al-Hujwīrī, 198; ʿAṭṭār, 777). He inherited a great deal of wealth after his fa…