N.'s monograph is a revision of her Ph.D. thesis (Cambridge, 2019) and reconceptualises Christianisation of the Roman Empire in the fourth century as a ‘crisis of knowledge’ in which ‘competitive cultural reassessment’ played a decisive role. The writings of Emperor Julian are viewed as key to such interpretative competition, described by N. as a ‘politics of interpretation’ (p. xiii), that involved Christian and non-Christian thinkers who offered reflections from their respective viewpoints on Roman history and the use of paideia (the intellectual culture of the Graeco-Roman upper class) to legitimise their access to political power. Christians – such as Lactantius, Eusebius of Caesarea, and the emperors Constantine and Constantius II – relied on adapting earlier models of a philosopher-ruler while interpreting history in order to present an image of the ideal Christian emperor. Seen against this background, N. contends that Julian's writings and imperial policies responded critically to Christian control of meaning and the Roman past by engaging questions that concerned the relationship between philosophy and divine oversight in ways that corresponded to the approach of his Constantinian predecessors while contradicting them. However, Julian's death in battle against the Persians in 363 ce after an eighteen-month reign provided Christians such as Gregory of Nazianzus with opportunities to display the supposed superiority of their own interpretative systems to those of Julian and supporters such as Themistius and Libanius. For N., the application of duelling religious criteria for philosophical rule created a ‘positive feedback loop’ (p. xiii) between emperors and bishops that strengthened episcopal power in the socio-political realm in relation to rival bishops, non-Christian thinkers and even emperors during the fourth century.

An extraordinary range of literary source material is analysed persuasively in the overall construction of N.'s argument throughout the book. Julian's surviving body of writings is insightfully examined, along with detailed interpretations of key works by John Chrysostom, Synesius of Cyrene and Eunapius of Sardis, joining those Christian and non-Christian authors noted above. A wealth of information enriches every section of each chapter as N. combines an intuitive reading of ancient works in the areas of theology, philosophy, poetry and politics with mastery of vast amounts of secondary scholarship. However, the book is so full of information, explanation and analysis that clarity may be sacrificed as it can be somewhat difficult for readers to wade through the minutiae in order to follow N.'s arguments. For example, the introduction meanders for 30 pages in setting up N.'s argument before revealing her approach in an outline of the chapters that seems oddly brief considering the length of each one. The chapters themselves are anywhere between 30 and 60 pages in length; and while readers will undoubtedly find the discussions informative and stimulating, I believe it remains more difficult than it needs to be – even for a scholarly monograph – for readers to get at the core of N.'s thought.

Despite this relatively minor criticism, each chapter connects to the whole rather well. Rather than relying on chronological order, N. constructs her argument around Julian's literary output as pivotal for understanding ‘how Constantinian propaganda transformed the Roman political and ideological discourse’ so that this emperor [Julian] is no longer read in isolation among a long line of otherwise Christian rulers but as part of the same rhetorical and political context (p. 305). Part 1, containing the first two chapters, centres on Julian's writings produced while he was Caesar under Constantius II (355–360 ce). Part 2, covering Chapters 3 and 4, deals with Julian's sole rule as Augustus (361–363 ce) in reaction to both Constantius II and mainly his father, Constantine the Great. Part 3 (Chapters 5 and 6) explores Julian's death in 363 ce, which proved a convenient ‘proof’ for Christian thinkers responding to the late emperor's campaign to push Christianity back into the socio-cultural and political margins that their kind of wisdom rightly guided emperors while protecting the empire. A brief conclusion wraps up the book's discussion.

N. joins a long-standing scholarly trend exploring how Roman emperors portrayed or had themselves presented in public by means of written language – whether in literary texts, inscriptions or coins, for example.Footnote ¹ Similar work has also continued regarding Christianity, Christian emperors and ‘Christianisation’ in the Roman Empire.Footnote ² One of the most recent book-length studies to examine such territory has been M. Marcos's Emperors and Rhetoricians (2023), which analyses fourth-century imperial panegyric in order to show how this kind of communication could be used to create or take advantage of existing political opportunities. Whereas Marcos focuses on Constantius II and Julian as rhetoricians, N. sets her study of Julian's self-presentation as an intellectual philosopher-ruler firmly within a broader Constantinian framework by including Constantine himself in her assessment. Other authors – for instance D.N. Greenwood (Julian and Christianity: Revisiting the Constantinian Revolution [2021]) or H. Drake and J. Harries in a recent edited volume by N. Baker-Brian and S. Tougher (H. Drake, ‘“But I Digress …”: Rhetoric and Propaganda in Julian's Second Oration to Constantius’, pp. 35–46, at 42, and J. Harries, ‘Julian the Lawgiver’, pp. 121–36, at 131–2, in: N. Baker-Brian and S. Tougher [edd.], Emperor and Author: The Writings of Julian the Apostate [2012]) – have also considered Julian's writings, religious motivations and intellectual qualities related to his style of rule against a Constantinian background. N.'s contribution in this regard lies in her overall analysis of Julian's self-presentation as a true philosopher-ruler in contrast to Constantine and Constantius II, whose respective public self-images as intellectuals relied on Christianity that (for Julian) represented false wisdom. Whereas Constantine reinterpreted the classical culture informing paideia through a lens that embraced Christianity as that culture's fulfilment and Constantius II characterised non-Nicene Christianity as superseding it, Julian developed his self-representation in terms that were analogous with but antagonistic towards the Christian approaches of his two predecessors. Yet, Julian's death after a short reign confirmed for Christian thinkers that their interpretations of imperial access to the divine correctly represented true wisdom resulting in subsequent emperors’ public identifications with competing understandings of Christianity until Theodosius the Great legislated in favour of Nicene theology (for the edict of Theodosius, see Cod. Theod. 16.1.2). This shift in competing interpretative systems from ‘Christian vs. non-Christian’ to ‘Nicene Christian vs. non-Nicene Christian’ necessarily involved a loss of access to political power and cultural significance by non-Christians accompanied by their gain by bishops representing either interpretation of Christianity. With the eventual victory of Nicene Christianity towards the end of the fourth century, not only had Nicene bishops gained ascendancy over their ecclesiastical rivals but even in a sense over emperors as illustrated by Ambrose of Milan's conflicts with Theodosius.

N. thus offers a highly informed, contextually based narrative of religion, philosophy and power in the fourth-century Roman Empire that is persuasive in its perception of shifts among various rival interests competing for supremacy over history and meaning.