Scholar, bp. of Kashkar, and cath. (741–751). Born in (the vicinity of) Kashkar in 641 as son of Brik Ṣebyaneh (‘Blessed be His Will’). He received his education in the School of Seleucia-Ctesiphon and was for a certain time bp. of Kashkar before his election as cath. in 741. In the sixth year of his Catholicate a conflict between Aba and the clergy of Seleucia-Ctesiphon arose; the latter accused the cath. of having illegally taken the possessions of the city’s School. According to a letter written by Aba to the director, the teachers, and the other ‘brothers’ of the School, these charges were brought against him while he stayed outside the patriarchal seat for some time (probably for reasons of health). According to some medieval sources the cath. retired in a monastery of al-Wāsiṭ for a year, but returned to Seleucia-Ctesiphon after the conflict was settled. Aba is known as the author of different works which, except for ‘the Letter to the leaders of the School’, are lost: the Book of the Governors (Ktābā d-esṭraṭige), a Commentary on the Theologian (Gregory of Nazianzus), a Commentary on some works concerning dialectics (probably some books of the ‘Organon’ of Aristotle), a Homily on the Martyr Zakhe, and Exegetical Homilies (Memre puššāqāye). From the latter many fragments and extracts have been preserved in the Gannat Bussāme, containing the exegesis of passages from Gen., Num., Isa., and the four Gospels. These fragments and extracts are of great importance for the cultural and intellectual history of the Ch. of E. for at least three reasons: 1.  they represent the genre of exegetical prose homilies in a style which shows a strong influence from and a very sophisticated use of Greek rhetoric; 2. they show a very dynamic and varied exegetical tradition, in which not only influences from the works of Theodore of Mopsuestia but also from the works of John Chrysostom and from the ancient tradition of the School of Edessa become noticeable; 3. they present interesting early examples of apologetic and polemic dispute in response to Islamic criticism of Christian tenets such as the Trinity and the Divinity of Christ. Although Aba is reported to have maintained as cath. good relations with the Muslim governor of Iraq, Yūsuf b. ʿUmar al-Thaqafī, his homilies testify that he took a fierce polemical stand against the anti-Christian proclamations that the Arab authorities propagated in his days.