Usurpation was a constant possibility in the late Roman Empire. Although a usurper did not attempt to change the system of governance but simply to replace the ruler, the constant threat of usurpation deeply impacted the application and maintenance of power in the Late Roman Empire and drove changes in Roman political institutions, society and culture. Joachim Szidat’s Usurpator tanti nominis presents an important new analysis of the phenomenon. The book concentrates on the period between the death of Constantine the Great and the fall of the Western Empire but examines it with attention to prior and subsequent developments. The book is organized into five chapters, including introduction and conclusion, with an appendix that contains seven topical excursuses and several timelines.
Chapter 1 provides a historiographical and methodological overview of the problem. Szidat intends this book to provide the late Roman sequel to Egon Flaig’s 1992 work on the Principate. The reforms of Diocletian and Constantine altered the Roman state and thus usurpations and imperial responses to them unfolded quite differently from what happened in the earlier periods. Diocletian instituted reforms that consolidated power in the hands of the imperial court and introduced a structured system of co-emperorship and succession to combat usurpation. The Tetrarchic system did not last, but its institutions formed the basis of the late Roman imperial power. After Constantine, dynastic legitimacy again played an important role in the maintenance of power. Szidat draws attention to the military, political and ideological processes of usurpation by which a claimant gained legitimacy from the ruling emperor or wrested it from him. The central questions he asks are: ‘Who can become emperor?’ and ‘How does a usurper keep power?’
Szidat calls attention to the fact that usurpation came from a variety of quarters, from junior imperial colleagues in the case of Julian, who was of the ruling dynasty and a Caesar, to military commanders who were completely outside the institutional and social core of power, such as Magnus Maximus or Constantine III. Different backgrounds and processes of coming to power required different strategies for maintaining power, from negotiation and accommodation to outright war.
Chapter 2 examines how usurpations were perceived and how a successful usurper could go from tyrant to emperor. Here, Szidat calls attention to the changing nomenclature of usurpation and considers a range of other words and phrases applied to usurpers. A usurper could be called a tyrant, but so could a legitimate emperor. The word usurpator is used in the modern sense first under Valentinian, after which it appears the letters of Ambrose to Theodosius and in Ammianus. Szidat underscores that was not a technical term nor did it serve only to designate one who illegitimately took power. Ultimately, whoever held power could be legitimate, despite how they came to power.
Chapter 3 analyzes how legitimate emperors transferred power, secured power once elevated, and dealt with co- emperors. Szidat explores the ritual processes of accession drawing on the excerpts of Peter the Patrician in Constantine VII’s Book of Ceremonies. Szidat draws attention to the places of the various stakeholders and power sources—army, consistorium, Senate and comitatus —in securing a new emperor’s hold on power. While armies were the only deciding forces in the age of the soldier emperors, the various constituencies of the court ( comitatus, consistorium) exerted a legitimizing and stabilizing force in the transfer of power. In these cases, the army was called on to acclaim an emperor, but, as the case of Julian shows, this did not guarantee automatic legitimacy.
Chapter 4 then applies this same method of analysis to the usurper. Szidat catalogs different forms that usurpations could take, from those that took place on the margins of legitimacy and with grudging accommodation from the emperor in power, to assassinations and military challenge. The author explores the similarities and differences with legitimate accessions in the accession ceremonial of usurpations and the different power bases that could propose and support a usurper. The majority of the chapter analyzes which groups and individuals could be successful in their usurpation attempts, exploring several important examples. The chapter concludes with a short consideration of the role of non-Romans in usurpation, both internal and external.
Chapter 5 provides a conclusion wherein Szidat stresses the social rather than legal or military foundations of imperial power. He also provides an important perspective on how the Roman world’s experience of usurpations catalyzed institutional change, especially with regard to the emperor’s relationship with Roman and non-Roman elites. This process has the potential to be quite productive for future studies. He draws attention to the distance that grew between the Western and Eastern Empires as well as changes within the internal compositions of their societies. The excursuses and, especially, the chronological tables in the appendices are very valuable and will be an important resource in and of themselves.
In sum, the book not only provides an authoritative treatment of the problem, but a stimulating and productive methodological approach.