It is the country of the Zab or Diab rivers, and either includes the whole of Eastern Assyria between the mountains and the Tigris, or more strictly is applied to the region between the Upper and Lower Zab, which consists of two large plains separated from each other by the Karachok hills.  In this way Arbelitis, the plain between the Karachok and Zagros, would fall within Adiabene, but it is sometimes made a distinct region, in which case Adiabene must be restricted to the flat between the two Zabs, the Tigris, and the harachok.  Chalonitis and Apolloniatis, which Strabo seems to place between these northern plains and Susiana, must be regarded as dividing between them the country south of the Lesser Zab, Apolloniatis (so called from its Greek capital, Apollonia) lying along the Tigris, and Chalonitis along the mountains from the pass of Derbend to Gilan.  Chalonitis seems to have taken its name from a capital city called Chala, which lay on the great route connecting Babylon with the southern Ecbatana, and in later times was known as Holwan.  Below Apolloniatis, and (like that district) skirting the Tigris, was Sittacene, (so named from its capital, Sittace which is commonly reckoned to Assyria, but seems more properly regarded as Susianian territory.) Such are the chief divisions of Assyria east of the Tigris.

West of the Tigris, the name Mesopotamia is commonly used, like the Aram-Naharaim of the Hebrews, for the whole country between the two great rivers.  Here are again several districts, of which little is known, as Acabene, Tigene, and Ancobaritis.  Towards the north, along the flanks of Mons Masius from Nisibis to the Euphrates, Strabo seems to place the Mygdonians, and to regard the country as Mygdonia.  Below Mygdonia, towards the west, he puts Anthemusia, which he extends as far as the Khabour river.  The region south of the Khabour and the Sinjar he seems to regard as inhabited entirely by Arabs.  Ptolemy has, in lieu of the Mygdonia of Strabo, a district which he calls Gauzanitis; and this name is on good grounds identified with the Gozan of Scripture, the true original probably of the “Mygdonia” of the Greeks.  Gozan appears to represent the whole of the upper country from which the longer affluents of the Khabour spring; while Halah, which is coupled with it in Scripture, and which Ptolemy calls Chalcitis, and makes border on Gauzanitis, may designate the tract upon the main stream, as it comes down from Ras-el-Ain.  The region about the upper sources of the Belik has no special designation in Strabo, but in Scripture it seems to be called Padan-Aram, a name which has been explained as “the flat Syria,” or “the country stretching out from the foot of the hills.”  In the later Roman times it was known as Osrhoene; but this name was scarcely in use before the time of the Antonines.