Dustegerd stood upon the spot where now are seen the vast ruins of Kesra-Shirene. These have been described by Sir R. Ker Porter. "We are told, that the city of Dustegerd was the most stationary residence of Khosroo Purviz, and that it contained his most superb palace, treasury, and public buildings. There he passed his winters, with the beautiful object of his idolatry[46]; and thence he flew with her from the conquering arms of the emperor Heraclius. We entered upon a chain of hills, amongst which our road led in the most circuitous and intricate mazes I had ever trod; heights and depths, ravines, dry or water courses, rugged promontories, short stony plains, in short, every species of mountain difficulties, diversified our path for full fifteen miles, till we arrived at a once formidable barrier, not far from which we caught a view of the meandering river Zohaub. All along the alpine bridge we mounted, runs a massy wall of large hewn stone, which, in many places, like a curtain, closes the openings left by nature in the rocky bulwarks of the country. It had evidently been intended for a defence against any hostile approach from the eastward, and, on passing it, we went through what had formed one of its gates." Journeying on a mile or two further, the traveller came to a second wall, still higher and stronger, and from that ran a third wall, which partly enclosed a large angular space. On various spots lay large stones of a great length, and hollowed in the middle, as if they were the remains of some ancient covered channel to convey water. This is still called the aqueduct of Khosroo Purviz; and the natives told Sir Robert, that it was one of the works constructed by that prince to win the smiles of his beloved Shirene. Numerous fragments and continuations of the great rampart wall tracked their way, till they came to the ruins of another wall, the position and extent of which seemed to declare it to have been one side of the battlements of some large and ancient city. This they were informed was Kesra-Shirene.