In 209 A.D. Volagases IV was succeeded by his son Volagases V, under whom in 212 A.D. the fatal troubles in Persia began; while in 213 A.D. his brother Artabanus rose as rival claimant of the kingship, and the civil war lasted for many years. A fresh danger arose when Tiridates, a brother of Volagases IV, who had long been a refugee with the Romans and had accomplished Severus’ campaign of 199 A.D., escaped, in company with a Cilician adventurer, the cynic Antiochus, to the court of his nephew Volagases; for the emperor Antoninus (Caracalla) demanded their surrender, and obtained it only by a declaration of war (215 A.D.). About the same time Artabanus gained the upper hand, and in 216 A.D. he held Ctesiphon and its district; but Volagases still held out in the Greek cities of Babylonia, as his tetradrachms prove (till 222 A.D.). Artabanus’ strength lay in the north; the Arab histories of the Sassanians make him king of the Median region. Presently Artabanus had a war with Rome on his hands. An overwhelming Parthian force fell on Mesopotamia and refused to be appeased by the restoration of the captives of the previous year; Macrinus was beaten in two engagements and compelled to retire to Syria, abandoning the Mesopotamian plain; and in the winter of 217-218 A.D. he was glad to purchase peace for an indemnity of 50,000,000 denarii (£1,774,298 or $8,871,490). In or about 222 A.D. Artabanus must also have displaced his brother in Babylonia. PERSIA CONQUERS PARTHIA [Sidenote: [217-228 A.D.]] Persia, which dealt the last blow to the Arsacids, had through the whole Parthian period held an isolated position, and is so seldom mentioned that our knowledge of its history and native princes is almost wholly due to recently found coins. The emblems on the coins show that Persia was always loyally Zoroastrian, and at Istakhr stood the famous Fire temple of the goddess Anahedh. Its priest was Sassan, whose marriage with a Bazrangian princess, Rambehisht, laid the foundation of the greatness of his house, while priestly influence, which was very strong, doubtless favoured its rise. Pabak, son of Sassan, and Ardashir, son of Pabak, begin the history of the Sassanian dynasty, which occupies the next chapter. Artabanus did nothing to check the rise of the new power till Ardashir had all Persia in his hands (224 A.D.) and had begun to erect a palace and temple at Gor (Firuzabad). Nirofar, king of Elymais, was then sent against him, but was defeated, and now Ardashir passed beyond Persia and successively reduced Ispahan (Farætacene), Ahwaz (Elymais), and Mesene.