In the study of Late Antiquity, the transition from a world recognisable as the Graeco-Roman world to a world that saw a different configuration of power in the west and the rise of Islam in the east is a period of great significance. H. seeks to comprehend the historical process that brought about this change, and asks to what extent the impetus and the inevitability of the process should be found in the long reign of Justinian, which dominates the first half of the sixth century, or within the consequences of his reign, which played out in the second half. A familiar argument is that Justinian's military action in the western provinces and other expensive projects put an intolerable strain on resources and left the empire vulnerable. The initial clue, however, to H.’s judgement on Justinian's success is in the optimistic headline title, ‘Rome Resurgent’: he does not subscribe to the view that the recovery of North Africa and Italy, which took longer than the initial victories suggested, caused social and economic hardship, and put pressure on military resources needed for protecting the eastern frontier, was not ultimately worth it. A careful analysis of the ‘balance sheet’ in the later chapters proves otherwise.

However, that is not to say that H.’s view of the emperor is positive. The second, but equally central, aim of the book is to probe the character of Justinian: was he a romantic visionary or was he desperately seeking a successful venture to keep his throne and demonstrate the divine legitimacy of his rule? H. comes down very much in favour of the latter view, demonstrating repeatedly that Justinian pursued a policy of ‘western adventurism’, when circumstances allowed, in order to distract attention from the less successful aspects of his reign, enhance his popularity and enrich the treasury.

The link between the treasury, the military and the governance of empire is made explicit in Chapter 2, ‘The Military-Fiscal Complex’, in which H. emphasises the difference between modern governments, which provide a wide range of services in return for taxes, and pre-modern governments, whose main function was to make war. An important essay in its own right, this chapter investigates the organisation of the army and the attempts of late Roman governments to fund sufficient forces to keep the empire safe, the fiscal policies and taxes that developed, and the relationship between the emperor and the local elite. It is not surprising that it is the causes, course and consequences of Justinian's wars – and especially those in the west – that form the meat of this book, although there is a place for social, cultural and religious policies, too, when they intersect with the main line of investigation.

I started by mentioning Chapter 2 because it furnishes so much of the framework of the book, but it is in fact the first three chapters that set the scene of Justinian's reign. Although forming almost one third of the book, this is hardly a superficial introductory narrative. In the first chapter, ‘In This Sign Conquer’, we return to Constantine's dream and the Christianisation of the empire, but the key message is that military victory remained as essential to the ideology of a late Roman emperor as it had to his earlier predecessors. The third chapter, ‘Regime Change in Constantinople’, explores the immediate background of Justinian's accession, emphasising the politics of the succession. H. ranges himself firmly with those who believe that Justin always intended Justinian should succeed him, and that uncle and nephew worked closely to achieve their shared imperial aims during the 520s.

The following 150 pages form the nucleus of the book. Chapter 4, ‘The Last Desperate Gamble’, takes us as far as Sicily when the consequences of the first few years of Justinian's sole rule had come to a head. To the popularity gained from the new tough stance against Persia, and the support (at least from the capital) from the switch in religious policy, Justinian could add the achievement of the codification of the laws. But these successes were reversed almost immediately by the defeats suffered in the Persian conflict and the Nika riot. H. argues that a military conquest was what Justinian needed to restore belief in the legitimacy of his rule, and so he turned first to North Africa. However, only the serendipity of Gelimer's absence allowed Belisarius the opportunity to invade, hence the label ‘overseas adventurism’. This theme is picked up again in Chapter 6, ‘Rome and Ravenna’. The restoration of the ideological and political credibility of Justinian's regime brought about by the rapid military success led to the consideration of a military adventure in Italy that would tick all the right boxes: the ideological advantage of recovering Rome; the financial advantage of taxing the rich agricultural land of Italy; and the strategic advantage of controlling the Mediterranean once more. Unfortunately, the obliging Ostrogoths were holding Italy, and the first half of the chapter explores the manoeuvring required to bring about a state of warfare and, rehearsing views expressed elsewhere, an analysis of the Gothic force now living in Italy. Chapter 5, ‘Five Thousand Horse’, and the second half of Chapter 6 contain detailed narrative and analysis of the military operations in North Africa, and in Italy up to 540, and Chapter 9, ‘Insurgents’, considers the long operation to subdue the Moors in Africa, and to defeat the spirited resistance of Totila and Teias in Italy.

Chapter 7, ‘The Culture of Victory’, identifies the manifestations of imperial power that Justinian was able to pursue on the back of his military successes: principally, the codification of the laws, the construction of Hagia Sophia and more generally his new-style church architecture. H. draws particular attention to the personal role of Justinian in the religious ceremonies both within churches (illustrated in the San Vitale images) and on the streets of Constantinople. Although Justinian is always credited with an important role in church building, his personal contribution in developing the Christianisation of the Roman culture of empire (started by Constantine) is not normally made so explicit. It certainly fits with the idea of an emperor obsessed with proving the divine legitimacy of his rule, and it would be interesting to see further development of this idea.

The last section of this chapter considers Justinian's ultimately unsuccessful attempt to impose unity between the Chalcedonians and their opponents. This failure leads naturally to the difficult years of the early 540s, which are discussed in Chapter 8, ‘Our Brother in God’: the Persian success raises the issue of the financial cost and the ideological impact of Justinian's ‘western adventurism’. It is in Chapter 10, ‘The Western Empire of Justinian’, that H. asks whether Justinian had left his successors a ‘poisoned chalice’, an enlarged but structurally weakened empire that was ripe for collapse. He considers the geographical areas of North Africa, the Balkans, Italy and Spain, and concludes that despite the terrible human losses, the archaeological evidence (even from Italy) shows that the conquests resulted in a financial profit for the treasury in Constantinople.

Finally, in Chapter 11, ‘The Fall of the Eastern Empire’, H. lays the blame for the misfortunes of the seventh century on Justinian's successors (although his success may have encouraged them unwisely to attempt to emulate his military efforts). Alongside this specific conclusion, H. considers the strategy of empire more broadly, and concludes that the driving force was not so much an over-arching strategic foreign policy, but internal political agendas.

H. alternates between narrative and analysis, big-picture thinking and intensely detailed analysis, the sixth century and modern times. With the aim of seeking the causes of transition to the post-classical world, H. subjects aspects of Justinian – the emperor and his government – to a critique broadly set against conduct and policies in today's world. Not everyone will agree that these comparisons are always helpful, just as the slightly esoteric order and choice of material may cause readers to pause. The flowing writing makes the subject very accessible to all, but it is the careful and well-informed reader who will appreciate this distinctive picture of Justinian and will be encouraged to think about his important reign in new and interesting ways.