Armenia and Babylon along the course of the Euphrates, a fact which indirectly throws light upon the habits of earlier ages.  Diodorus, following Ctesias, declares that a number of cities were established from very ancient times on the banks of both the Tigris and the Euphrates, to serve as marts of trade to the merchants who imported into Assyria the commodities of Media and Paraetacene.  Among the most important of these marts, as we learn from Strabo, were Tiphsach or Thapsacus on the Euphrates, and Opis upon the Tigris.

It is from notices thus scanty, partial, and incidental, eked out by probability, and further helped by a certain number of important facts with respect to the commodities actually used in the country, whereof evidence has been furnished to us by the recent discoveries, that we have to form our estimate of the ancient commerce of the Assyrians.  The Inscriptions throw little or no light upon the subject.  They record the march of armies against foreign enemies, and their triumphant return laden with plunder and tribute, sometimes showing incidentally what products of a country were most in request among the Assyrians; but they contain no accounts of the journeys of merchants, or of the commodities which entered or quitted the country in the common course of trade.

The favorable situation of Assyria for trade has often attracted remark.  Lying on the middle courses of two great navigable streams, it was readily approached by water both from the north-west and from the south-east.  The communication between the Mediterranean and the Southern or Indian Ocean naturally—­almost necessarily—­followed this route.  If Europe wanted the wares and products of India, or if India required the commodities of Europe, by far the shortest and easiest course was the line from the eastern Mediterranean across Northern Syria, and thence by one or other of the two great streams to the innermost recess of the Persian Gulf.  The route by the Nile, the canal of Neco, and the Red Sea, was decidedly inferior, more especially on account of the dangerous navigation of that sea, but also because it was circuitous, and involved a voyage in the open ocean of at least twice the length of the other.

Again, Assyria lay almost necessarily on the line of land communication between the north-east and the south-west.  The lofty Armenian mountain-chains—­Niphates and the other parallel ranges—­towards the north, and the great Arabian Desert towards the south, offered difficulties to companies of land-traders which they were unwilling to face, and naturally led them to select routes intermediate between these two obstacles, which could not fail to pass through some part or other of the Mesopotamian region.