Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[69] But in no long time Artabanus died, and left his kingdom to his son Bardanes. Now this Bardanes came to Izates, and would have persuaded him to join him with his army, and to assist him in the war he was preparing to make with the Romans; but he could not prevail with him. For Izates so well knew the strength and good fortune of the Romans, that he took Bardanes to attempt what was impossible to be done; and having besides sent his sons, five in number, and they but young also, to learn accurately the language of our nation, together with our learning, as well as he had sent his mother to worship at our temple, as I have said already, was the more backward to a compliance; and restrained Bardanes, telling him perpetually of the great armies and famous actions of the Romans, and thought thereby to terrify him, and desired thereby to hinder him from that expedition. But the Parthian king was provoked at this his behavior, and denounced war immediately against Izates. Yet did he gain no advantage by this war, because God cut off all his hopes therein; for the Parthians perceiving Bardanes's intentions, and how he had determined to make war with the Romans, slew him, and gave his kingdom to his brother Gotarzes. He also, in no long time, perished by a plot made against him, and Vologases, his brother, succeeded him, who committed two of his provinces to two of his brothers by the same father; that of the Medes to the elder, Pacorus; and Armenia to the younger, Tiridates.