The Roman frontier with Persia in north-eastern Mesopotamia investigates the Roman city of Singara and the fortifications and roads in the surrounding area. The physical frontier between Rome and Persia has been little studied, in part because of the difficulty of access for scholars. In comparison with other parts of the Roman 'limes', this frontier was of great importance because it separated the two major civilisations of the early first millennium CE. Although the frontier stretched north to Armenia and the Black Sea, north-east Mesopotamia was for long periods the major area of confrontation. After a brief review of the history of north-east Mesopotamia and its role as the setting for repeated clashes between the two empires, the book focuses on Singara, its fortifications and the surrounding frontier zone. This town was one of the strongpoints on the Roman frontier as it existed up to 363 CE. The volume then addresses the ancient road network around Singara and the links to Nisibis and to the Khabur valley to the west. It makes use of old aerial photographs and satellite imagery to illustrate fortifications, roads and associated sites, in particular those mentioned in the Peutinger Table. A final chapter addresses the nature of the frontier in this region.