This account of parallel lives begins with a programmatic statement: ‘By using two persons as a case study, my book belongs to a recent historiographic trend reinserting individual agency back into a more structural analysis’ (p. 3). Susanna Elm's protagonists are human personalities in dialogue with each other and their epoch, rather than social trends and/or abstract notions. Recipients of the same paideia, the ‘Apostate’ and the ‘Theologian’, as Julian and Gregory were respectively nicknamed by posterity, were prolific writers with an irrepressible tendency to bare their souls to the public, a feature which complicates rather than facilitates the task of the biographer, who has to struggle with the whims of a constantly changing psychology. Both Julian and Gregory were committed ascetics, fervently devoted to their personal mission to shape not just the lives, but primarily the souls of the inhabitants of the Roman Empire. In order to reveal the important similarities, and also the ‘small, though significant differences’ (pp. 11, 13), between these two exact contemporaries who shared so much common ground, Elm devotes a considerable part of her book to a biographical narrative which she sets against a wider historical background (roughly part i, pp. 17–143). The detailed prosopographic analysis that she undertakes in this connection allows the reader to appreciate the intricacy of the social and intellectual networks which operated at elite level, cutting across the fabric of the traditional antinomies of paganism versus Christianity or orthodoxy versus heterodoxy. Gregory's brother Caesarius, an archiater sacri palatii and an imperial friend under Julian, the ‘Anomoian’ theologians Aetius and Eunomius, on whom the pagan emperor showered favours, and the Aristotelian Themistius, whom he ostentatiously kept at arm's length, are just examples of those shown in the course of the narrative to have closer connections – indeed evident elective affinities – with their ‘foes’, than with their natural allies. Subscribing to the ‘consensus’ scholarship of recent decades, Elm emphasises dialogue and interaction, rather than difference and conflict (‘the boundary between pagan and Christian was so porous that these terms lose their analytical value’: p. 11. cf. p. 216), and underlines the ubiquity of social intercourse among late antique elites, which inevitably results in the permeability of ideological frontiers. This is certainly valid in some cases, but on the whole tends to be the exception rather than the rule in late antiquity, when an increasing number of textual communities came into being.

In her introduction, Elm also announces her intention to write a ‘micro-social history of ideas' (p. 9), based on the dialogue between representatives of a variety of trends, with the antithesis oikeios-allotrios functioning as a tool of classification (pp. 167, 176–9, 199, 215ff., 360, 362, 379). As regards Gregory, she undertakes ‘to retranslate [him] from a Christian saint back into a classical philosopher’ (p. 13), mainly by dwelling on his use of Stoic and Neoplatonic concepts and terminology, such as homoiosis theo and oikeiosis pros theon. Conversely she is not interested in the major patristic influences on his theology, since ‘this has been excellently done by others’ (p. 9 n. 28). Her often bold interpretations are based on an analysis of Gregory's philosophical discourse in the context of literary genre and historical circumstance. A good illustration of this method is provided by her analysis of oration 2, generally known as Apology for his flight to Pontus, for which Elm adopts the title On priesthood, from the marginal notes of the manuscript tradition. By general scholarly consensus this oration is dated between Epiphany and Easter 362. Elm, however, decodes Gregory's reaction to the portentous events of the summer 362 in a way which enables her to date the oration a year later. In June 362 (when, as suggested by the author, Gregory might still have been a master of rhetoric in his native Nazianzos), Julian's Edict on Education prohibiting Christians from teaching the classics was published; shortly afterwards, Gregory's father, Bishop Gregory the Elder, signed a homoian document, thus becoming involved in a schism. Unable, according to Elm, to cope with the simultaneous crisis in his professional and his family life, Gregory fled from Nazianzos to the Pontus on 1 August 362 and in the peaceful retreat of Annesi he gathered his thoughts and eventually produced the ‘triptych’ of speeches 1 to 3. Elm's meticulous analysis of Oration 2 in the light of late antique Christian ethics and of the character and relationship of the two Gregories (pp. 138–203) results in the exoneration of the son (who at that point was already a priest ordained by his father) from any moral and formal transgression of duty: in an overprotective, even patronising manner, Gregory justifies the theological and behavioural faux pas of his beloved father by presenting him as a naïve, spontaneous man who could easily be laid astray (cf. the analysis of the funeral oration for his father, pronounced in 374: 201–21]).

The redating of oration 2 works in the general direction of the book. Gregory's actions and discourse are invariably interpreted (and sometimes explained away) to match the portrait of a psychologically consistent individual with programmatic thinking. Elm's reading of the invectives against Julian (orations 4 and 5) is another case in point: ignoring the letter and the tone of Gregory's prose (and also the unanimous approach of scholarship), and applying a structural analysis inspired by post-modern principles of political correctness, Elm reads these two polemical treatises against a dead enemy as products of profound and balanced thinking on the subject of logoi in the empire.

While attentive to the infinite nuance of heresy within Christianity, Elm fails to recognise the role played by heterodoxy in contemporary Hellenism. But the paideia forming the late antique elites was not a monolith (pace pp. 92, 107, 152). For one thing it was a much less homogeneous whole than its Hellenistic predecessor. The reason for this is to be sought in the hypertrophy (and variety) of the spiritual dimension which progressively came to dominate the educational process, transforming the field of culture into a battleground of conflicting forces. Various contenders, armed with their canonical scriptures and a formidable arsenal of interpretative rules, fought under the banner of specific textual communities for the truth of their own exegesis (pace pp. 12, 334). In this conceptual Babel, in which each group defined its identity by reference to and in contradistinction with the heretical Other (whose scriptures were branded as apocryphal), there was nevertheless still room for those who emerged as the recipients of a pre-late antique paideia, such as Themistius, to whom so much of the book is devoted.

Primarily a moral philosopher interested in the here-and-now, Themistius was indifferent to metaphysics, and for this reason not inimical to Christianity. The unbridgeable gulf separating the Platonic ontology, conceiving creation in terms of a geometric progression, from the Judeo-Christian model, which views it as an act of craftsmanship, was no concern of his. The spiritual dimension, which was of such paramount importance to both Gregory and Julian, is a missing article from the thinking of Themistius, who reads Aristotle as a philosopher within the Peripatetic tradition. Julian on the other hand belongs to a chain of thinkers whose outlook on Aristotle evolved from total or partial rejection (Numenius, Plotinus) to compromise and accommodation (Porphyry, Iamblichus). It was indeed by this perverse interpretation of Aristotle's metaphysics that the famous dogma of the agreement between Plato and his revisionist pupil could be formulated, a dogma on which the edifice of late Platonism rests. In absolute terms, Themistius' reading of Aristotle may be closer to the original text, but it is certainly miles apart from that of Julian who had been raised by his Neoplatonic teachers to believe in the exclusive correctness of their (and his own) understanding of a ‘spiritual Aristotle’.

It is from such premises that Julian attacks Themistius, in whom he sees a mere technician of philosophy unable to reach its metaphysical core, and a social opportunist. Assuming that the two men share a common understanding of Greek philosophy in general and of Aristotle in particular, Elm interprets Julian's Letter to Themistius not as an attack on its recipient and his ideology, but as a criticism of his patron, the emperor Constantius, whose policies Julian is about to reverse (p. 86). In a startling but wholly arbitrary hypothesis (which deals with in a cavalier manner, or ignores entirely, the assumptions of all earlier scholarship on the subject), Elm suggests that a first draft of Julian's Letter to Themistius was composed, presumably in 355, as a response to a now lost letter sent by Themistius to congratulate him on his accession to the rank of Caesar (p. 83), and that in 361 Julian did no more than revise his earlier (unpublished?) work (p. 106). As well as ignoring the tone of the specific text, and misreading Julian's philosophical argument in it, this hypothesis contradicts the systematic efforts of the new emperor towards proving in act and word his lack of resentment towards his deceased predecessor (ep. xxviii; Libanius, oration 18. 120; Mamertinus 27. 5). Indeed this lack of resentment was crucial to Julian's evolving of a dynastic theology built around the pattern of error (committed by Constantine) and redress (by Julian himself), in the context of which, far from being an active wrongdoer, Constantius emerges as an innocent victim of circumstances. Thus the statement that ‘Gregory conceived the philosophical life along the lines represented by Themistius and hence Constantius, in clear opposition to Julian’ (p. 156, cf. p. 477) shows a complete misunderstanding of the attitudes of all three people.

Of the three components of the book's subtitle it is the vision of Rome which most recommends itself to the reader's attention. The strength of the book consists in its emphasis on the political involvement of its two protagonists. They were both deeply engagé individuals, constantly and creatively involved in the politics of an oecoumene which, as Elm shows, they perceived as a spiritual entity. Enormous toil and erudition, linguistic mastery apparent in the translation of some of Gregory's more difficult prose, and attention to detail are the book's assets. Value judgements and repetitiveness are its faults. One cannot help feeling that a drastic reduction in the length of the book would have benefited its argument. Yet whether one agrees or not with her interpretations, Elm certainly opens the field to wider discussion.