In consequence of these and other circumstances of a similar nature, it happened that Alexander and Darius actually passed each other, without either of them being aware of it. Alexander advanced into Syria by the plains of Issus, marked _a_ upon the map, and a narrow pass beyond, called the Gates of Syria, while Darius went farther to the north, and arrived at Issus after Alexander had left it. Here each army learned to their astonishment that their enemy was in their rear. Alexander could not credit this report when he first heard it. He dispatched a galley with thirty oars along the shore, up the Gulf of Issus, to ascertain the truth. The galley soon came back and reported that, beyond the Gates of Syria, they saw the whole country, which was nearly level land, though gently rising from the sea, covered with the vast encampments of the Persian army.