M. Zerjadtke. Das Amt ‘Dux’ in Spätantike und frühem Mittelalter. Der ‘ducatus’ im Spannungsfeld zwischen römischem Einfluss und eigener Entwicklung.  Berlin: De Gruyter, 2018.

“The office of ‘Dux’ in Late Antiquity and the early Middle Ages“ is Michael Zerjadtke‘s dissertation, which was published in 2019 and submitted two years prior at the University of Hamburg. In a total of 7 chapters, it deals with the officer of the duces (sg. dux) in Late Antiquity and the early Middle Ages. Duces are generally translated as „military leaders” of the Roman army, and this office has as of yet not received comprehensive treatment in research.

With the aim of investigating and comparing the military, territorial and, if applicable, administrative-political areas of responsibility as well as the terms of office and the social rank of the duces, he deals with more than 40 known officers in the gentile successor kingdoms of Late Antiquity and the early Middle Ages until around the year 600.

After an introductory chapter, in which Zerjadke reviews the research history and his own preliminaries for the investigation, a chapter of the general preliminary considerations follows. Here, the author critically examines the available sources and provides working definitions of important terms. He also considers the original application of the term dux and how it developed within and outside of the Roman army.

The following two chapters examine the Alemanni and Burgundians, which differ from the southern kingdoms, insofar that the term dux is absent in the available sources of these peoples. This is expressed on the one hand by the prevalent use of the reges and on the other hand, as Zerjadtke suspects, by the general scarcity of such sources. A similarly sketchy picture is given by the sources on the Vandal Empire, in which the term dux is never mentioned. The author partly attributes this to the lack of distinctive military districts and officers administrating them.

Zerjadke puts the main focus of the book on the Ostrogothic and Visigothic kingdoms as well as on the Lombards and the Franks – again due to the written records. Thus, he discusses and analyses the mentions of duces in these groups before and after the formation of their own states. Based on this examination Zerjadke concludes that the Roman dux in the sources can only be compared to the early medieval one in terms of title, but not necessarily in terms of the fields of activity. Sometimes he deliberately discusses certain cases in detail: one of such examples is the Ostrogothic title dux Retiarum, which Zerjadke regards as an exceptional example of a stringent continuity from the Roman to the Eastern Gothic dux. The Lombard Gisulf as well as his successors in the ducat of Forum Iulii is also dealt with in detail, not least due to the falsely assigned grave in Cividale del Friuli. The account of their impact is handed down primarily by the resident chronicler and main source for the history of the Lombards in general, Paulus Diakonus.

The largest amount of sources, however, is preserved on the duces of the Franconian Empire. Here, 64 duces are known by name and their careers can be traced to a good extent. Zerjadke comes to the conclusion that the dux, as direct subordinate to the Merovingian king, was the highest official in the Frankish empire.

The compact but comprehensive outline of the office of the dux in the gentile empires of the early Middle Ages by M. Zerjadke is thus an excellent source on medieval military history and an important milestone in understanding late Roman Antiquity and medieval continuity. He accomplishes his goal of a diachronic and complete study of one particular military rank of that time. This is true not least because Zerjadke was able to discredit the assumption that there was a straightforward development of the meaning of the dux at all, as he demonstrates a break in the meaning and the area of ​​responsibility as well as the extent of power in the respective empires. Accordingly, this book provides a good source for the investigation of war cultures, especially when it comes to dealing with the Euro-Mediterranean military elite and their organisation.