The succeeding reigns have little bearing on history until we come to that of Bahrām Gūr,[53] which was signalised by a persecution of the Christians,[54] and a recommencement of warfare with Rome. Bahrām Gūr was worsted in the latter, and entered into a treaty with the Western Empire, which bound the contracting parties to tolerate the Christian and Zoroastrian cults respectively. The Romans further undertook to pay an annual subsidy towards the maintenance of the fortifications on the Dariel Pass[55] in the Caucasus, by which both kingdoms were protected from the inroads of the wild hordes of the North. Bahrām took advantage of his truce with the Romans to make an expedition into Bactria,[56] where he encountered the Ephthalites, or White Huns, whom, according to Persian accounts, he utterly defeated. We are told that the Khākān[57] of the “tribes of Transoxiana,” being informed that Bahrām and his court were immersed in luxury and had entirely lost their martial spirit, ventured to cross the Oxus and laid waste the whole of Khorāsān.[58] He was soon undeceived, for Bahrām, at the head of seven thousand men, fell upon the Turks by night, and put them utterly to rout, the Khākān perishing by the king’s own hand. Bahrām then crossed the Oxus and concluded a peace with his eastern neighbours.[59] Bahrām died in 438, and was succeeded by his son Yezdijerd II. During his reign of nineteen years his attention was engrossed by Armenia and by Khorāsān, where he suffered many reverses at the hands of the Ephthalites. On his death in A.D. 457 his two sons, Hormuz III. and Pīrūz, became rival claimants to the throne. Their father, who preferred the former, but feared a quarrel between the brothers, had given Pīrūz the governorship of a distant province, Sīstān. Pīrūz, on learning that his brother had seized the throne and won the support of the nobility, fled across the Oxus, and implored the chief Khākān[60] of the Ephthalites to espouse his cause. The Huns consented, and sent an army thirty thousand strong to his aid.[61] With this accession of strength, Pīrūz invaded Persia, and defeated his brother in a pitched battle. Hormuz III. thus lost his crown, and was put to death together with three of his nearest relatives. The reign of his successful rival was fraught with useful domestic measures. He had to contend against a famine which lasted for seven years; but, so prompt and effectual were the means adopted to combat it, that, if Tabari is to be believed, there was not a single death from starvation.[62] Pīrūz’s foreign policy was by no means so praiseworthy: though he owed his crown to the ready help of the Khākān of the Ephthalites, we find him in 480 freely attacking his benefactor’s son and successor. This apparent ingratitude is ascribed by Joseph Stylites to the intrigue of the Romans, whose jealousy of the power of Persia induced them to incite the Huns to attack her eastern frontier. Nöldeke suggests as the cause