by modern commerce was the so-called southern route. In the fifteenth century curious Oriental craft had brought their wares from eastern Asia across the Indian Ocean and up the Red Sea to some convenient port on the Egyptian shore; here their cargoes were trans-shipped via caravan to Alexandria and Cairo, marts of trade with the European cities of the Mediterranean. The completion of the Suez Canal, in 1869, transformed this route of medieval merchants into an avenue of modern transportation, incidentally realizing the dream of Portuguese and Spanish explorers of centuries before—a short, all-water route to the Indies. Less than forty years later the northern route of medieval commerce—from the "back doors" of China and India to the plains of European Russia—was opened to the twentieth-century locomotive. With the completion of the Trans-Siberian Railway in 1905 the old caravan trails were paralleled with steel rails. The Trans-Siberian system linked Moscow and Petrograd with Vladivostok and Pekin; the Trans-Caspian and Trans-Persian railways stretched almost to the mountain barrier of northern India; the Trans-Caucasian lines provided the link between the Caspian and Black Seas.
The heart of the central route of Eastern trade in the fifteenth century was the Mesopotamian Valley. Oriental sailing vessels brought commodities up the Persian Gulf to Basra and thence up the Shatt-el-Arab and the Tigris to Bagdad. At this point the route divided, one branch following the valley of the Tigris to a point north of Mosul and thence across the desert to Aleppo; another utilizing the valley of the Euphrates for a distance before striking across the desert to the ports of Syria; another crossing the mountains into Persia. From northern Mesopotamia and northern Syria caravans crossed Armenia and Anatolia to Constantinople. This historic highway—the last of the three great medieval trade-routes to be opened to
