The remaining years of Phraates--and he reigned for nearly twenty years after restoring the standards--are almost unbroken by any event of importance. The result of the twenty years’ struggle between Rome and Parthia had been to impress either nation with a wholesome dread of the other. Both had triumphed on their own ground; both had failed when they ventured on sending expeditions into the enemy’s territory. Each now stood on its guard, watching the movements of its adversary across the Euphrates. Both had become pacific. It is a well-known fact that Augustus left it as a principle of policy to his successors that the Roman Empire had reached its proper limits, and could not with advantage be extended further. This principle, followed with the utmost strictness by Tiberius, was accepted as a rule by all the earlier Caesars, and only regarded as admitting of rare and slight exceptions. Trajan was the first who, a hundred and thirty years after the accession of Augustus, made light of it and set it at defiance. With him re-awoke the spirit of conquest, the aspiration after universal dominion. But in the meantime there was peace--peace indeed not absolutely unbroken, for border wars occurred, and Rome was tempted sometimes to interfere by arms in the internal quarrels of her neighbors--but a general state of peace and amity prevailed--neither state made any grand attack on the other’s dominions--no change occurred in the frontier, no great battle tested the relative strength of the two peoples. Such rivalry as remained was exhibited less in arms than in diplomacy and showed itself mainly in endeavors on either side to obtain a predominant influence in Armenia. There alone during the century and a half that intervened between Antony and Trajan did the interests of Rome and Parthia come into collision, and in connection with this kingdom alone did any struggle between the two countries continue. Phraates, after yielding to Augustus in the matter of the standards and prisoners, appears for many years to have studiously cultivated his good graces. In the interval between B.C. 11 and B.C. 7, distrustful of his subjects, and fearful of their removing him in order to place one of his sons upon the Parthian throne, he resolved to send these possible rivals out of the country; and on this occasion he paid Augustus the compliment of selecting Rome for his children’s residence. The youths were four in number, Vonones, Seraspadanes, Rhodaspes, and Phraates; two of them were married and had children; they resided at Rome during the remainder of their father’s lifetime, and were treated as became their rank, being supported at the public charge and in a magnificent manner. The Roman writers speak of these as “hostages” given by Phraates to the Roman Emperor; but this was certainly not the intention of the Parthian monarch; nor could the idea well be entertained by the Romans at the time of their residence.