The Romans had watched the rise of Ardashir with apprehension. There is no question that he cherished the design of seizing upon as many of their Asiatic possessions as he could. He gained some successes at first, but was forced to give ground when Alexander Severus marched against him. The history of the empire of the Sassanids was conditioned from the outset by its relations with Rome. Peace was again and again concluded between the two, but they invariably looked upon each other as adversaries, and as adversaries of equal rank. Under capable rulers and tolerable internal conditions Rome (that is Byzantium) maintained the ascendency of the European over the Asiatic, but circumstances were frequently adverse, and the Persians heaped disgrace upon the Roman name. This struggle fills the chief place in the political history of the Sassanids. SASSANIAN POWER [Sidenote: [236-260 A.D.]] Istakhr remained the capital in theory, as Persepolis had formerly been. There stood the Fire temple of the royal house, in which the heads of vanquished foreign kings were hung up among other trophies. But the real metropolis was Ctesiphon, the capital of the Arsacids, and Seleucia, which was divided from it only by the Tigris and which Ardashir restored under the name of Veh-Ardashir (good Ardashir). The rich country in which this double city lay was neither geographically nor ethnographically a part of Iran, for the deep valley was peopled principally by Semites; the choice of it as the seat of government was due to the precedent set by the elder empire and in part, probably, to its nearness to Roman territory. We cannot in all cases be sure over which countries Ardashir ruled at the end of his life, for the national tradition tells of some conquests really made by his successors, and others which the Sassanids never made at all. But Ardashir won and consolidated a great empire that held together for four centuries, giving a powerful blow to the system of vassal states, which had become more and more prevalent under the Arsacids, and reducing most of these states to provinces. SAPOR FIGHTS ROME