SELEUCIA-ON-THE-TIGRIS, so called from its position, in order to distinguish it from the other towns of that name, stood at the point where an artificial canal connected the waters of the Euphrates and Tigris, 40 miles N. of Babylon. It was a large and important city, containing, it is said, in the time of its prosperity, a population of 600,000 souls; and it was second in commercial importance only to Alexandria. Having been the capital of the Macedonian possessions in the East, Seleucia still retained, after the fall of that empire, an independent position, and a thoroughly Greek character. It was governed by a senate of 300, was strongly fortified, and thus able to defy the power of the Parthians, whose empire reached almost to the gates. The oriental city of Ctesiphon rose on the other side of the Tigris, only three miles off, and finally supplanted Seleucia in the power and splendour which it had inherited from the old Babylon. It was the Romans, however, who took and sacked Seleucia, notwithstanding its hostility to their enemies, 165 A.D. From this blow the city never recovered; and the place relapsed into a marshy desert.