When we turn from the remote parts of the Orient to Western Asia we find ourselves in regions much better known to the Western world, though the traditional geography of these regions, founded on classical and Biblical authority, persisted in encyclopedic writings hardly influenced at all by the contacts that in reality had been established. The _De imagine mundi_, Gervase of Tilbury’s _Otia imperialia_, and other similar works add little to what Isidore and Orosius had written. Between the Indus and Tigris lie many countries, Arachosia, Parthia, Assyria, Persia, Media, all forming a harsh and mountainous tract called in Scripture “India” but more generally known as Parthia. Fire had been discovered in Persia.[1347] The Tigris, so called because it is as swift as a tiger, rises from a common source with the Euphrates in the mountains of Armenia.[1348] Thence the two rivers separate, leaving a long space between them known as Mesopotamia; the Tigris encircles Assyria and empties into the Dead Sea! Peter Comestor and the author of the _De imagine mundi_ accepted the views of Isidore regarding the source of the Tigris in the highlands of Armenia,[1349] but the latter adds to the already prevailing confusion by stating that both rivers of Mesopotamia debouch into the Mediterranean Sea. Gervase, on the other hand, corrects the error of the author of the _De imagine mundi_ by making them flow into the Red Sea (or Indian Ocean),[1350] as was depicted on most maps. _Mesopotamia_ Mesopotamia was said to be famous as the site of Nineveh and of Chaldea, where astronomy was discovered;[1351] and Gervase of Tilbury dilates on the immense size of the walls of Babylon.[1352] Regarding Babylon, it is refreshing to find in Otto of Freising’s _Chronicon_ some really up-to-date information which he had derived from Frutolf.[1353] In the first place, he makes a careful distinction between Babylon and Cairo, to which the name of Babylon was commonly given. “Old Babylon,” he added, “as we learn from reliable men from across the seas, is partly inhabited at the present day and now called Baldach [Baghdad]. Part, however, as you would expect from the words of prophecy, is a desert waste extending for ten miles as far as the tower of Babel. The part which is inhabited and called Baldach is very large and populous.” He explains that here is the seat of the greatest priest of the Persians, whom they call “Caliph,” and who holds in some respects a position among these pagans parallel to that which the Pope at Rome holds among Christians. With Baghdad we have at last come to a city that was actually visited and described during our period by Western Europeans whose descriptions have come down to us. The Jewish travelers, Benjamin of Tudela and Petachia of Ratisbon, appear to have sojourned in the Mesopotamian city in the seventh and ninth decades of the twelfth century respectively. _Benjamin of Tudela on Baghdad_