In my first book, Culture and Religion in Merovingian Gau, AD 481-751 (Leiden, 1995), I studied the shared meanings, attitudes and values, and the symbolic forms in which they were expressed or embodied in Merovingian society. Although too often depicted as a barbaric society, with the full pejorative meaning of these words – a view partly derived from Gregory of Tours, our main source and sometimes our only one to the first century of Merovingian rule – Merovingian Gaul, I have argued, was a direct continuation of the Roman civilisation in terms of social standards, morals and culture. Merovingian culture, as I have demonstrated, had some distinctive literary aspects, and it was basically Christian, indeed deeply shaped by Christian liturgy. Superstitions and pagan survivals, which, in the past, have too often dominated the discussion of Merovingian culture and religion, were marginal and far from representative. Moreover, through a detailed examination of the sources I established that the prevailing notion of Merovingian society as Christian by name but pagan by practice was, in fact, generated by Carolingian propaganda concerning the Merovingian past. The anti-Merovingian propaganda was created and disseminated by the Carolingians, their supporters and scholars. Its purpose was to undermine and discredit the Merovingian dynasty and to pave the way for legitimating the Carolingian usurpation. Paradoxically, it is still effective and deceives historians who, relying heavily on Carolingian sources, have produced a deriding picture of Merovingian Gaul. The conclusions of my book were rather unorthodox and provocative at the time, and consequently stirred much debate and discussion among scholars. Nevertheless, it seems that most scholars nowadays would largely agree with the favourable picture of Merovingian culture and religion I have portrayed in my book.

In a series of papers (many of which were presented in conferences, workshops and seminars throughout the world) I continued to explore the religious culture of early medieval Francia. My studies concentrated on a variety of issues, from visionary literature to biblical commentaries, with a particular interest in liturgy. This special interest paved the way for my book, The Royal Patronage of Liturgy in Frankish Gaul to the Death of Charles the Bald (877) (London, 2001). The examination of the royal patronage of liturgy in the Frankish kingdoms provided a remarkable opportunity to re-examine some of the most prevailing notions regarding the Frankish liturgy, such as the traditional assumption that the liturgy of Frankish Gaul during the Carolingian period was a unified liturgy and, moreover, the product of a unified Frankish Church. Similarly, the reports on the Romanisation of the Frankish liturgy under Pippin III and Charlemagne, which, in the past, were accepted at face value, appear to be part of what I would call ‘the Carolingian rhetoric of reform’. A careful examination of the sources from early medieval Francia demonstrates how the Frankish kings, and foremost among them Charlemagne, realised the political power within the patronage of liturgy, and therefore made ample use of it as a political means of royal propaganda. Through liturgy they disseminated political messages and ideology in an attempt to shape the ‘public opinion’, and this is precisely why they invested vast amounts of landed property and privileges in patronising liturgical activity. The introduction of liturgy as an extremely informative source for the study of the political culture and the social practices of the early medieval West was rather unique and innovative, and many subsequent studies followed suit. 

The study of numerous unpublished manuscripts was a significant part of my research over the years. This activity also brought some new findings and discoveries, such as The Sacramentary of Echternach, which I have edited for the Henry Bradshaw Society; the Pseudo-Theophilus’ Commentary on the Four Gospels, which I have discussed in a separate paper; and the Arundel manuscript of the Annales Mettenses Priores, which is the subject of another paper.  

In another book, entitled Roman Barbarians: The Royal Court and Culture in the Early Medieval West, I explore the place of the royal court and the mechanisms of patronage which operated through it in several kingdoms of the early Middle Ages. The general approach is based on the conviction that the roots of later medieval developments, and especially of the so-called Carolingian Renaissance, are to be sought in the centuries immediately succeeding the period of Roman rule. It was in this period that Roman and Christian ideals were mingled with indigenous Germanic practices, and thus sow the seeds of what we now call ‘the medieval civilisation’. In this book I discuss the literary activities associated with several early medieval royal courts, such as the court of the Vandal court of Thrasamund (496-523), The Ostrogothic court of Theoderic the Great (493-526), the Visigothic court of Sisebut (611-620), the Frankish court of Dagobert I (623-639), and the Lombard court of Desiderius (757-774). The comparative analysis of these barbarian courts highlights the continuities and similarities, as well as the various differences, that characterised the cultural activity of the early medieval West, and it clarifies how crucial the barbarian precedents are for assessing and understanding the Carolingian achievement and, subsequently, later medieval culture and society.

Together with Prof. Dr. Stefan Esders (Freie Universität Berlin) I co-directed the GIF project East and West in the Early Middle Ages: The Merovingian Kingdoms in Mediterranean Perspective. The aim of this project was to break free of traditional views on the course of Merovingian history, and to study the Merovingian kingdoms of the early Middle Ages in a broader Mediterranean context. Our working hypothesis was that apart from being post-Roman Barbarian kingdoms, deeply rooted in the traditions and practices of the western Roman Empire, the Merovingian kingdoms had complicated and multi-layered social, cultural and political relations with their eastern Mediterranean counterparts, that is, the Byzantine Empire and the Umayyad Caliphate. Not only were the Merovingians aware of the politics and culture of Byzantium and its relations to the Persians, they also had a fair amount of knowledge on the ins and outs of the Muslim East from the seventh century onwards. By analysing Merovingian and Eastern accounts, as well as various archaeological findings and artefacts, we attempted to offer a new perspective on the history of Merovingian Francia and its relations with the Eastern Mediterranean, and to  clarify the importance and significance of eastern religious and cultural phenomena to the understanding of the social, as well as the political history of the early medieval West. This project resulted in the puclication of two collections of essays: The Merovingian Kingdoms and the Mediterranean World: Revisiting the Sources, ed. Stefan Esders, Yitzkak Hen, Pia Lukas and Tamar Rotman (Bloomsbury: London, 2019); and East and West in the Early Middle Ages: The Merovingian Kingdoms in Mediterranean Perspective, ed. Stefan Esders, Yaniv Fox, Yitzhak Hen and Laury Sarti (Cambridge University Press: Cambridge, 2019).