Now look at a modern map of Asia. Between Arabia and Persia there is a long valley watered by the Tigris and Euphrates, rivers which rise in Armenia and flow into the Persian Gulf. This region was the traditional "cradle of the human race." Around and beyond was a great world, a world with great surging seas, with lands of trees and flowers, a world with continents and lakes and bays and capes, with islands and mountains and rivers. There were vast deserts of sand rolling away to right and to left; there were mountains up which no man had climbed; there were stormy seas over which no ship had ever sailed. But these men of old had never explored far. They believed that their world was just a very little world with no other occupants than themselves. They believed it to be flat, with mountains at either end on which rested a solid metal dome known as the "firmament." In this shining circle were windows, in and out of which the sun would creep by day and the moon and stars by night. And the whole of this world was, they thought, balanced on the waters. There was water above, the "waters that be above the firmament," and water below, and water all round. [Illustration: BABYLONIAN MAP OF THE WORLD ON CLAY. Showing the ocean surrounding the world and the position of Babylon on the Euphrates. In the British Museum.] Long ages pass away. Let us look again at the green valley of the Euphrates and Tigris. It has been called the "nursery of nations"--names have been given to various regions round about, and cities have arisen on the banks of the rivers. Babylonia, Mesopotamia, Chaldea, Assyria--all these long names belonged to this region, and around each centres some of the most interesting history and legend in the world. Rafts on the river and caravans on the land carried merchandise far and wide--men made their way to the "Sea of the Rising Sun," as they called the Persian Gulf, and to the "Sea of the Setting Sun," as they called the Mediterranean. They settled on the shores of the Caspian Sea, on the shores of the Black Sea, on the shores of the Red Sea. They carried on magnificent trade--cedar, pine, and cypress were brought from Lebanon to Chaldea, limestone and marble from Syria, copper and lead from the shores of the Black Sea. And these dwellers about Babylonia built up a wonderful civilisation. They had temples and brick-built houses, libraries of tablets revealing knowledge of astronomy and astrology; they had a literature of their own. Suddenly from out the city of Ur (Kerbela), near the ancient mouth of the Euphrates, appears a traveller. There had doubtless been many before, but records are scanty and hard to piece together, and a detailed account of a traveller with a name is very interesting.