In the consulship of Caius Cestius and Marcus Servilius, some Parthian nobles came to Rome, without the knowledge of their king Artabanus. Dread of Germanicus had made that prince faithful to the Romans and just to his people, but he subsequently changed this behaviour for insolence towards us and tyranny to his subjects. He was elated by the wars which he had successfully waged against the surrounding nations, while he disdained the aged and, as he thought, unwarlike Tiberius, eagerly coveting Armenia, over which, on the death of Artaxias, he placed Arsaces, his eldest son. He further added insult, and sent envoys to reclaim the treasures left by Vonones in Syria and Cilicia. Then too he insisted on the ancient boundaries of Persia and Macedonia, and intimated, with a vainglorious threat, that he meant to seize on the country possessed by Cyrus and afterwards by Alexander. The chief adviser of the Parthians in sending the secret embassy was Sinnaces, a man of distinguished family and corresponding wealth. Next in influence was Abdus, an eunuch, a class which, far from being despised among barbarians, actually possesses power. These, with some other nobles whom they admitted to their counsels, as there was not a single Arsacid whom they could put on the throne, most of the family having been murdered by Artabanus or being under age, demanded that Phraates, son of king Phraates, should be sent from Rome. "Only a name," they said, "and an authority were wanted; only, in fact, that with Cæsar's consent, a scion of the house of Arsaces should show himself on the banks of the Euphrates."
Complete Works of Tacitus. Tacitus. Alfred John Church. William Jackson Brodribb. Sara Bryant. edited for Perseus. New York. : Random House, Inc. Random House, Inc. reprinted 1942.
