Bp. of Dayro d-Mor Matay and learned author. Born in Barṭelle , his baptismal name was probably Yaʿqub. He studied grammar under Yoḥannan bar Zoʿbi in the famous E.-Syr. monastery of Beth Qoqe (in Adiabene ), and philosophy under Kāmāl al-Dīn Mūsā b. Yūnus at Mosul . He was first a monk and subsequently abbot and bp. of the Dayro d-Mor Matay, with the episcopal name Severos (according to Schrier, however, Severos was his baptismal name and Yaʿqub his episcopal one, but this would seem surprising). His surviving writings consist of 1. ‘The Book of Treasures’, a theological compendium in four parts, composed in 1231; this covers the Trinity, the Incarnation, Divine Providence, and the Creation; 2. ‘The Book of Dialogues’, in two Books, the first of which covers grammar, rhetoric, poetry, and eloquence (on the richness of the Syriac language), while the second deals with philosophical topics, divided into two parts, the first covering logic and syllogisms, the second with sections on definitions, ethics, physics and physiology, mathematics and music, and metaphysics; 3. two verse letters addressed to physicians; and perhaps 4. a symbol of faith. He also wrote some other works, now lost; these included a commentary on the liturgical services.