It was probably not more than two or three years after the events above narrated, that Volagases found himself in circumstances which impelled him to send a petition to the Roman Emperor for help.  The Alani, a Scythian people, who had once dwelt near the Tanais and the Lake Mseotis, or Sea of Azof, but who must now have lived further to the East, had determined on a great predatory invasion of the countries west of the Caspian Gates, and having made alliance with the Hyrcanians, who were in possession of that important pass, had poured into Media through it, driven King Pacorus to the mountains, and overrun the whole of the open country.  From hence they had passed on into Armenia, defeated Tiridates, in a battle, and almost succeeded in capturing him by means of a lasso.  Volagases, whose subject-kings were thus rudely treated, and who might naturally expect his own proper territories to be next attacked, sent in this emergency a request to Vespasian for aid.  He asked moreover that the forces put at his disposal should be placed under the command of either Titus or Domitian, probably not so much from any value that he set on their military talents as from a conviction that if a member of the Imperial family was sent, the force which accompanied him would be considerable.  We are told that the question, whether help be given or no, was seriously discussed at Rome, and that Domitian was exceedingly anxious that the troops should go, and begged that he might be their commander.  But Vespasian was disinclined for any expenditure of which he did not recognize the necessity, and disliked all perilous adventure.  His own refusal of extraneous support, when offered by his rival, rendered it impossible for him to reject Volagases’s request without incurring the charge of ingratitude.  The Parthians were therefore left to their own resources; and the result seems to have been that the invaders, after ravaging and harrying Media and Armenia at their pleasure, carried off a vast number of prisoners and an enormous booty into their own country.  Soon after this, Volagases must have died.  The coins of his successor commence in June, A.D. 78, and thus he cannot have outlived by more than three years the irruption of the Alani.  If he died, as is most probable, in the spring of A.D. 78, his reign would have covered the space of twenty-seven years.  It was an eventful one for Parthia.  It brought the second period of struggle with the Romans to an end by compromise which gave to Rome the shadow and to Parthia the substance of victory.  And it saw the first completed disintegration of the Empire in the successful revolt of Hyrcania—­an event of evil portent.  Volagases was undoubtedly a monarch of considerable ability.  He conducted with combined prudence and firmness the several campaigns against Corbulo; he proved himself far superior to Paetus; exposed to attacks in various quarters from many different enemies, he repulsed all foreign invaders and, as against them, maintained intact the ancient