The subject of this book can be defined in three different ways: geographically, chronologically and linguistically. In geographical terms I mean by 'the Roman Near East' all those areas which lie between the Taurus Mountains and Egypt, and which were, or came to be, under Roman rule. The region concerned overlaps the territories of eight modern states: Turkey, Iraq, Syria, Lebanon, Jordan, Israel, Egypt and Saudi Arabia. To the west it is of course bounded by the Mediterranean, and to the north, somewhat less clearly, by Mount Amanus and the foothills of the Taurus. To the east and south the eventual limits of Roman military occupation did not correspond with any very definite geographical boundaries. The middle Euphrates, which for long served as a symbolic boundary between the empires of Rome and of Parthia, ceased to do so in the course of the second century. With that great change, to which I will come back many times, the Roman Empire in the east expanded decisively beyond the Mediterranean seaboard, with consequences of immense significance. By the end of the third century Roman control extended to, and in some not very clear sense beyond, the upper-middle Tigris. In the south-west of the area, similarly, the Roman military presence has left traces in part but not all of the Hedjaz, the barren mountain-range running along the eastern side of the Red Sea. What seems to be the furthermost Roman outpost here is Medain Saleh, a little over 300 km north of Medina.
The area concerned thus represents a large section of the Fertile Crescent; its definition as fertile reflects the fact that all of it shades off into what is often called desert, but is in fact at almost all points not desert but a flat, largely dry and often very stony steppe, in places coloured dark-grey or black from the presence of volcanic rock. To emphasise the fact that the zone along whose margins a great line of Roman roads and forts, from the Red Sea to