Tigris,[4] in the form of an oblong, and surrounded it with strong fortifications. The two longer sides measured 150 stades each, the two shorter sides 90 stades each, so that the whole circuit was 480 stades. The walls reached a height of 100 feet, and were so thick that there was room in the gangway for three chariots to pass each other. These walls were surmounted by 1500 towers, each of the height of 200 feet. As to the inhabitants of the city, the greater number and those of the most importance were Assyrians, but from the other nations also any who chose could fix his dwelling here, and Ninus allotted to the settlers large portions of the surrounding territory, and called the city Ninus, after his own name. When the city was built Ninus resolved to march against the Bactrians. He knew the number and bravery of the Bactrians, and how difficult their land was to approach, and therefore he collected the armies of all the subject nations, to the number of 1,700,000 foot soldiers, 210,000 cavalry, and towards 10,600 chariots of war. The narrowness of the passes which protect the entrance to Bactria compelled Ninus to divide his army. Oxyartes, who at that time was king of the Bactrians, had collected the whole male population of his country, about 400,000 men, and met the enemy at the passes. One part of the Assyrian army he allowed to enter unmolested; when a sufficient number seemed to have reached the plains he attacked them and drove them back to the nearest mountains; about 100,000 Assyrians were slain. But when the whole force had penetrated into the land, the Bactrians were overcome by superior numbers and scattered each to his own city. The rest of the cities were captured by Ninus with little trouble, but Bactra, the chief city, where the palace of the king lay, he could not reduce, for it was large and well-provisioned, and the fortress was very strong.