Theologian and monastic author. The main sources for Babai’s life are Ishoʿdnaḥ’s ‘Book of Chastity’ (chap.  39), Toma of Marga’s ‘Book of Superiors’ (I, ch. 27 and 29), and the Chronicle of Siirt (chap. 84). Born in Beth ʿAynatha (in Beth Zabdai), he studied at the School of Nisibis under Abraham of Beth Rabban. He subsequently became a monk of the ‘Great Monastery’, founded in 571 by Abraham of Kashkar (d. 588). Later, he moved to Beth Zabdai to found his own monastery there, but in 604 he returned to the Great Monastery, where he had been appointed abbot, in succession to Dadishoʿ. During the interregnum (609–28) following the death of the Cath. Grigor, the Ch. of E. was administered jointly by the Archdeacon and Babai, the latter having the title ‘Visitor of the monasteries’. He died shortly after the death of Khusrau II (628), who had not allowed the appointment of a successor to Grigor.

Babai’s writings cover four main topics:

1. Christology. His ‘Book of the Union, on the divinity and humanity (of Christ) and on the prosopon of the union’, remains a fundamental statement of the Christology of the Church to this day. It is composed in seven books, of which the seventh may originally have belonged to another work. The ‘Book of the Union’ was edited (with LT) by A. Vaschalde (CSCO 79–80; 1915); there is an unpublished ET by M. Birnie. In the same volume of the CSCO there is also a short treatise ‘Against those who say “Just as the body and soul are one qnomā, so too God the Word and the Man are one qnomā” ’. An excerpt arguing that ‘two natures’ (in the incarnate Christ) implies ‘two qnome’ features in a late collection of Christological texts (ed. with ET by L. Abramowski and A. Goodman, Nestorian Christological Texts [1972], vol. 1, 207–9 [Syr.], vol. 2, 123–5 [ET]).

2. Monastic topics. Of great significance, for its learning as well as for its length, is his Commentary on Evagrius of Pontus’s ‘Gnostic Chapters’ (ed. with GT by Frankenberg, 1912). Babai also wrote a Commentary on Mark the Monk’s ‘Spiritual Law’ (unpublished; study by G. Krüger, in OC 44 [1960], 46–74). A collection of short ‘Useful Counsels on the Ascetic Life’ are also unpublished, but there is an ET by G. Chediath, Babai the Great. Some Useful Counsels on the Ascetic Life (Moran Etho 15; 2001). Babai wrote a set of Rules for monks, preserved only in Arabic translation (ed. with ET, A. Vööbus, Syriac and Arabic Documents regarding Legislation relative to Syrian asceticism [1960], 176–84).

3. Hagiography. In his Life of Gewargis (ed. P. Bedjan, Histoire de Mar Jabalaha, de trois autres patriarches, d’un prêtre et deux laïques, nestoriens [1895; repr. 2007], 424–8) Babai gives a list of his hagiographical works, but of these only the Life of Mihramgushnasp/Gewargis (martyred in 615) survives in full (ed. Bedjan, Histoire de Mar Jabalaha, 416–571; GT by G. Hoffmann, 1880). Unfortunately the only ms. of a woman martyr, Christina, breaks off soon after the beginning (ed. Bedjan, Acta Martyrum et Sanctorum, vol. 4, 201–7).

4. Liturgy. Two tešbḥātā (‘Our Father who is in heaven, holy is his nature...’ and ‘Blessed is the Compassionate One who in his grace...’) are specifically attributed to him (though some mss. have a different attribution); the first of these also features in the Maronite Šḥimto (Thurs. Lilyo). A Hymn for the Commemoration of the Greek Doctors is also attributed to him (ms. Cambridge Add. 1980, f. 210r; not found in T. Darmo’s edition of the ḥudrā).

5. Parts of a work on the monastic life are preserved in a ms. (M20N) of the ‘New Finds’ at the Monastery of St. Catherine, Mount Sinai.

A large number of other works by Babai have not survived (ʿAbdishoʿ states that he wrote ‘83 volumes’ in all).