But if these were his thoughts, he had miscalculated. Augustus, from the time that he heard of the Armenian troubles, and of the support given to them by Parthia, seems never to have wavered in his determination to vindicate the claims of Rome to paramount influence in Armenia, and to have only hesitated as to the person whose services he should employ in the business. He would have been glad to employ Tiberius; but that morose prince had deserted him and, declining public life, had betaken himself to Rhodes, where he was living in a self-chosen retirement. Caius, the eldest of his grandsons, was, in B.C. 2, only eighteen years of age; and, though the thoughts of Augustus at once turned in this direction, the extreme youth of the prince caused him to hesitate somewhat; and the consequence was that Caius did not start for the East till late in B.C. 1. Meanwhile a change had occured in Parthia. Phraates, who had filled the throne for above thirty-five years, ceased to exist, and was succeeded by a young son, Phraataces, who reigned in conjunction with the queen-mother, Thermusa, or Musa.
The circumstances which brought about this change were the following. Phraates IV. had married, late in life, an Italian slave-girl, sent him as a present by Augustus; and she had borne him a son for whom she was naturally anxious to secure the succession. According to some, it was under her influence that the monarch had sent his four elder boys to Rome, there to receive their education. At any rate, in the absence of these youths, Phraataces, the child of the slave-girl, became the chief support of Phraates in the administration of affairs, and obtained a position in Parthia which led him to regard himself as entitled to the throne so soon as it should become vacant. Doubtful, however, of his father’s goodwill, or fearful of the rival claims of his brothers, if he waited till the throne was vacated in the natural course of events, Phraataces resolved to anticipate the hand of time, and, in conjunction with his mother, administered poison to the old monarch, from the effects of which he died. A just Nemesis for once showed itself in that portion of human affairs which passes before our eyes. Phraates IV., the parricide and fratricide, was, after a reign of thirty-five years, himself assassinated (B.C. 2) by a wife whom he loved only too fondly and a son whom he esteemed and trusted.