Imperatores castra dedicaverunt: Security, Army Bases, and Military Dispositions in Later Roman Egypt (Late Third-Fourth Century)

This study takes a fully integrated archaeological and documentary approach to examine major themes in the security of later Roman Egypt and the responses to those issues by Diocletian (284-305) and his tetrarchic colleagues at the turn of the third to fourth century. It argues that tetrarchic reforms there were essentially pragmatic and diverse, responding to a variety of challenges rather than being monocausal, as some scholars have suggested, and demonstrates that they were spread over several decades rather concentrated in a single moment, such as Diocletian's visit to Egypt in 298. Whereas Diocletian's reforms are often presented as a radical departure from the Principate, reassessment suggests a substantial degree of continuity, deriving in part from continuity in the physical and human geography of Egypt. Discussion here first examines the crises of security that Egypt underwent in the last decades of the third century, including external invasion, frontier conflicts with nomads, and internal revolt, then considers the responses to those crises enacted by Diocletian and his colleagues, in terms of the forts and fortresses of the tetrarchic period and military dispositions known through documentary sources such as contemporary papyri and the later Notitia dignitatum. Concluding remarks offer a brief evaluation of the functions of the Roman army in fourth-century Egypt.