Thus it was due not to the success and strength of the Parthians but entirely to the principles of Roman policy as de fined by Augustus that their empire appears as a second great independent power, side by side with Rome. The precedence of the Caesars, indeed, was always admitted by the Arsacids; and Phraates IV. soon entered into a state of dependency on Rome by sending (9 B.c.) four of his sons as hostages to Augustus—a convenient method of obviating the danger threatened in their person, without the necessity of killing them. In 4 B.c., however, Phraates was assassinated by his favourite wife Musa and her son Phraates V. In the subsequent broils a Parthian faction obtained the release of one of the princes interned in Rome as Vonones I. (A.D. 8). He failed, however, to maintain his position for long. He was a stranger to the Parthian customs, and the feeling of shame at dependency on the foreigner was too strong. So the rival faction brought out another Arsacid, resident among the Scythian nomads, Artabanus II., who easily expelled Vonones —only to create a host of enemies by his brutal cruelty, and to call forth fresh disorders.
Similar proceedings were frequently repeated in the period following. In the intervals the Parthians made several attempts to reassert their dominion over Armenia and there install an Arsacid prince ; but on each occasion they retreated without giving battle so soon as the Romans prepared for war. Only the dynasty of Atropatene was finally deposed and the country placed under an Arsacid ruler. Actual war with Rome broke out under Vologaeses I. (51-77), who made his brother Tiridates king of Armenia. After protracted hostilities, in which the Roman army was commanded by Cn. Domitius Corbulo, a peace was con cluded in A.D. 63, confirming the Roman suzerainty over Armenia but recognizing Tiridates as king (see CORBULO). Tiridates him self visited Rome and was there invested with the diadem by Nero (A.D. 66). After that Armenia continued under the rule of an Arsacid dynasty.
These successes of Vologaeses were counterbalanced by seri ous losses in the east. He was hampered in an energetic campaign against Rome by attacks of the Dahae and Sacae. Hyrcania, also, revolted and asserted its independence under a separate line of kings. A little later the Alans, a great Iranian tribe in the south of Russia—the ancestors of the present-day Ossets—broke for the first time through the Caucasian passes, and ravaged Media and Armenia—an incursion which they often repeated in the following centuries.
On the other side, the reign of Vologaeses I. is characterized by a great advance in the Oriental reaction against Hellenism. The line of Arsacids which came to the throne in the person of Artabanus II. (A.D. o) stands in open opposition to the old kings with their leanings to Rome and, at least external, tinge of Hellenism. The new regime obviously laid much more stress
on the Oriental character of their state, though Philostratus, in his life of Apollonius of Tyana (in reality a fantastical romance which contains scarcely any historical information), states that Vardanes I. (A.D. the rival king to the brutal Gotarzes (A.D. was a cultivated man (Vit. Ap. i. 22, 28, 31 sqq.); and Vologaeses I. is distinguished by the excellent relations which subsisted all his life between himself and his brothers Pacorus and Tiridates, the kings of Media and Armenia. But the coins of Vologaeses I. are quite barbarous, and for the first time on some of them appear the initials of the name of the king in Aramaic letters by the side of the Greek legend. The Hellenism of Seleucia was now attacked with greater determination. For seven years (A.D. the city maintained itself in open rebellion (Tac. Ann. xi. 8 seq.), till at last it surrendered to Vardanes, who in consequence enlarged Ctesiphon, which was afterwards fortified by Pacorus (A.D. 78-105: V. Ammian, 23, 6, 23). In the neigh bourhood of the same town Vologaeses I. founded a city Vologesocerta (Balashkert), to which he attempted to transplant the population to Seleucia (Plin. vi. 122: cf. Th. Noldeke in Zeitschr. d. deutsch. morgenl. Gesellschaft, xxviii., 1 oo). Another of his foundations was Vologesias (the Arabian Ullaish), situated near Hira on the Euphrates, south of Babylon, which did appre ciable damage to the commerce of Seleucia and is often men tioned in inscriptions as the destination of the Palmyrene caravans.
After Vologaeses I. follows a period of great disturbances. The literary tradition, indeed, deserts us almost entirely, but the coins and isolated literary references prove that during the years A.D. 77 to 147, two kings, and sometimes three or more, were often reigning concurrently (Vologaeses II. 77-79, and 111.-147; Pacorus 78–c. 105; Osroes 106-129; Mithradates V. also Artabanus III. 80-81; Mithradates IV. and his son Sana truces II. 115; and Parthamaspates T16-117). Obviously the empire can never have been at peace during these years, a fact which materially assisted the aggressive campaigns of Trajan (113-117). Trajan resuscitated the old project of Crassus and Caesar, by which the empire of Alexander as far as India was to be won for western civilization. In pursuance of this plan he reduced Armenia, Mesopotamia and Babylonia to the position of imperial provinces. On his death, however, Hadrian immediately reverted to the Augustan policy and restored the conquests. Simultaneously there arose in the east the powerful Indo-Scythian empire of the Kushana, which doubtless limited still further the Parthian possessions in eastern Iran.