Grant Bayliss’ The Vision of Didymus the Blind offers an important contribution to the rehabilitation of this controversial fourth-century author. Alternately condemned as an ‘Origenist’ and praised as ‘pro-Nicene’, Didymus was best known for his biblical commentaries, most of which were lost until a momentous discovery at Tura in 1941. Focusing on these Tura commentaries, Bayliss argues that virtue lies at the heart of Didymus’ theology and exegesis. Because of this, he claims, Didymus represents an ascetic interpretation of Origen's multivalent legacy that aligns him more with Gregory of Nyssa than with Evagrius.

Bayliss organises his ten chapters into three parts. Part I, ‘Background’, covers a host of issues including how to adjudicate the conflicting depictions of Didymus in later authors; what it means to refer to him as the teacher of the Alexandrian catechetical school; and how to categorise his exegetical approach. Through these considerations, an image emerges of an urban ascetic teacher sought out by transient students like Jerome and Rufinus but with no official relationship to anything like an institutional school. At times, part I reads like academic throat-clearing, the type of details best excised from the monograph version of a doctoral thesis (which this is). Yet Bayliss successfully orients these background conversations toward his primary theme of virtue and the training of the soul, thereby making this section integral to his overarching argument. (The one exception is chapter 3, ‘Footprints in the Sand: Assessing the Didymean Corpus’, which would work better as an excursus or appendix, yet will no doubt prove invaluable in its detail for future research on Didymus.)

In part II, ‘Didymus and the Doctrine of Virtue’, Bayliss presents a comprehensive analysis of virtue as central to Didymus’ exegetical and theological vision. Moreover he elucidates the relationship of virtue to other more controversial aspects of Origen's legacy, such as the pre-existence of souls, the salvation of the devil and the Trinity. Didymus emphasises the eternal ontological reality of virtue as it exists in God, in contrast to the non-being of sin. Thus, though Didymus affirms the pre-existence of souls, he does so to emphasise their origin in virtue – the same virtue to which they return via the Christian life of participation in God. Similarly, though he is ambiguous on the fate of the devil, Didymus must maintain the possibility of his redemption because of the ontological priority of virtue. All of this connects to his pro-Nicene conception of the Trinity in which virtue cannot be associated with a lesser divine person who in turn participates in the true divinity of the Father; rather, the ontological priority of virtue resides in the undivided, eternal Trinity from whom all creation comes, by whom all creation is sustained, and to whom all creation – especially rational souls – is teleologically oriented.

For part III, Bayliss turns to the problem of sin and why we turn from our native virtue. He focuses on the Stoic notion of pre-passion (propatheia). Whereas Origen references the idea in passing, Didymus makes this theory central to his psychology in order to explain the common origins of affection and volition. This allows Didymus to explain the ‘passions’ of Christ as well as the biblical affirmations that all, even the venerated saints, have sinned.

Though he insists that Didymus is not without inconsistency, Bayliss has presented a compelling interpretation of Didymus’ holistic theological vision. There are a few places, however, where the reader desires a bit more clarity. For instance, throughout part II Bayliss emphasises that ‘virtue has an eternal and substantial existence in God’, but he repeatedly qualifies this claim by asserting that virtue ‘is not the same as God’ (p. 96). It is unclear what Bayliss means by this distinction or why he repeatedly makes it. One is left curious as to how Didymus’ understanding of divine simplicity fits with this theme of an eternal, substantial existence in God that is not identical with God.

Such qualms notwithstanding, Bayliss’ study offers a fruitful reading of Didymus as an urban ascetic teacher developing a particular trajectory in Origen's legacy amidst the complex context of the late fourth century. This book will prove helpful for any future studies of Didymus, late antique exegesis or theological anthropology.