After having set forth the new state organisation, with which the sinking Rome was soon to contend, we resume the thread of our narrative. Antoninus, son and successor of Severus, not a warrior and statesman like his father, but a dissolute caricature of both, must have had the design--so far as in the case of such personages we can speak of design at all--to bring the East entirely into the Roman power. It was not difficult to place the princes of Osrhoene and of Armenia, after they had been summoned to the imperial court, under arrest, and to declare their fiefs forfeited. But on the arrival of the news a revolt broke out in Armenia. The Arsacid prince Tiridates was proclaimed king, and invoked the protection of the Parthians. Thereupon Antoninus put himself at the head of a large military force, and appeared in the East in the year 216, to put down the Armenians, and in case of need also the Parthians. Tiridates himself at once gave up the cause as lost, although the division sent to Armenia subsequently encountered vehement resistance there; and he fled to the Parthians. The Romans demanded his surrender. The Parthians were not inclined on his account to enter into a war, the more especially as just then the two sons of king Vologasus V., Vologasus VI. and Artabanus, were in bitter feud over the succession to the throne. The former yielded when the Roman demand was imperiously repeated, and delivered up Tiridates. Thereupon the emperor desired from Artabanus, who had meanwhile obtained recognition, the hand of his daughter for the express object of thus obtaining the kingdom by marriage, and of bringing East and West under one rule. The rejection of this wild proposal[76] was the signal for war; the Romans declared it, and crossed the Tigris. The Parthians were unprepared; without encountering resistance the Romans burnt down the towns and villages in Adiabene, and ruthlessly destroyed even the old royal tombs at Arbela.[77] But Artabanus made the utmost exertions for the next campaign, and put into the field a powerful force in the spring of 217. Antoninus, who had spent the winter in Edessa, was assassinated by his officers just as he was setting out for this second campaign. His successor Macrinus, unconfirmed in the government and held in little repute, at the head, moreover, of an army defective in discipline and tone and shaken by the murder of the emperor, would gladly have rid himself of a war wantonly instigated and assuming very serious proportions. He sent the prisoners back to the Parthian king, and threw the blame of the outrages committed on his predecessor. But Artabanus was not content with this; he demanded compensation for all the devastation committed, and the evacuation of Mesopotamia. Thus matters came to a battle at Nisibis, in which the Romans had the worst. Nevertheless the Parthians, partly because their levy seemed as though it would break up, perhaps also under