The study of Roman imperial coinage as an instrument of political communication has seen numerous publications in recent years. Most of these focus on a particular reign or region, although several take a longer-term perspective. Donatien Grau ambitiously investigates the period from Octavian up to the late fourth century c.e. Unlike most other qualitative studies on coin iconography, other visual media have not been included in the analysis. What interests G. is how coin images relate to previous ones, how in the course of time a numismatic memory was built up and how this was employed by successive emperors to convey not only links to illustrious predecessors and their achievements, but also the essence of Empire at large.

The voluminous work starts out by exploring how Augustus anchored the propagation of his reign in the coin imagery of the Republic, that of the Hellenistic rulers and that of the imperatorial period. It follows this development for the Julio-Claudian dynasty and the turmoil after Nero's death (part one, five chapters). From this point onwards G. postulates three principles at work in the selection and design of coin images. First, continuity, which relates to the repetition of a stock repertoire (deities, personifications, the imperial bust, etc) to stress the continuity of rule and the core values of emperor and Empire. Secondly, factuality, which refers to actual events (e.g. a specific victory) being visualised on coins in order to highlight the current emperor's contribution to the success of Rome. Finally, and most importantly for this book, ‘transversalité’, which in G.'s definition basically means the intertextuality between coin images: from outright copying and replicating previous images to allusions to and quotations of the same. Through this ‘transversalité’, a narrative of imperial rule and Empire is created and communicated.

The remainder of the book is dedicated to this third principle. In the second part (consisting of three chapters), G. explores a number of case studies, including the triumphal arch, the image of Sol and the galley. In the third part (again three chapters), G. addresses intertextuality between coin iconography and textual sources (the Res Gestae of Augustus in the coinage of Nero, or Carausius’ citations of Vergil), between coin iconography and contorniates, and the phenomenon of restoration coinages (explicitly duplicating a coin image of a previous emperor). The final part (four chapters) approaches the topic from a different angle and discusses how coins and their images are described and understood in Latin literature. Through this lens, G. tries to demonstrate that the goal of ‘transversalité’ was achieved and numismatic memory played a part in narratives and reflections on Roman imperial power and rule. The book ends with a plea to treat coin images as a specific kind of textual source and to include them to a much larger degree in historical research.

Everyone who has taken a closer look at imperial coinage will have noted the presence of stock images on the one hand, and the re-appearance time and again of specific types or renderings of specific themes. However, G.'s close reading of the images uncovers many more subtleties in these quotations. His lyrical prose offers convincing observations, but doubt remains at to how far this really was a conscious policy laden with symbolic meaning. This is in part caused by the anecdotal character of his methodology. After discussing the first imperial dynasty in quite some detail — though even there ignoring Tiberius’ bronze coinage, but including that of Caius — the remainder of the book is not so systematic in its treatment of the material. That leaves one to wonder how far his case studies are representative of a larger phenomenon, or what dictated the choice of his case studies in the first place. Likewise in his treatment of the historical sources — both as reflected on coinage and as reflecting these coins — it is not made clear whether his examples are just a sample, or all the evidence there is. Especially when taking such a longue durée approach, at least some quantification of the material would have been beneficial — and would have made the argument more convincing. Since digital resources now make the typology of the imperial coinage available at a mouse-click, such an endeavour would not have been impossible. A further issue is that G. does not really address the question on how this ‘intertextuality’ functioned in practice. Was there an archive of dies or coins at the mint? Who was the audience for these subtle allusions? Could references to coins issued a century earlier really resonate? Or were the undeniable present references and citations more an intellectual game for the initiated? These questions remain to be discussed, but G.'s work certainly forms the basis for these further considerations.

On the technical level, the reader acutely misses a more detailed index in such a rich work. The one supplied is brief and curiously ignores e.g. Carausius, to whom a whole subchapter is dedicated. Furthermore, in a work on coin iconography, one would expect the numerous illustrations offered to be labelled and numbered in some way and referred to in the text. As it is, it is up to the numismatic expertise of the reader to link the images strewn throughout the text to the examples and descriptions offered by the author.