Over a period of some five centuries, Europe was transformed by the emergence of barbarian kingdoms in the regions of the former Roman Empire. In the turbulent post-Roman world, the Christian church and its bishops had considerable sway, as these kingdoms developed new institutions such as Christian kingship. Warlike kingdoms competed with each other and took on projects of political consolidation, religious accommodation, and conversion. Religious imperatives shaped the understanding of political culture, alongside aristocratic consensus and cooperation. The Franks ultimately dominated...