hands, and of the Roman prisoners, it was observed that they said nothing about restoring the strongholds which they had taken, or resuming the position of Roman tributaries.  On the contrary, they required that all Roman soldiers still in their country should be withdrawn from it, and that their independence should henceforth be respected.  As Severus was not inclined to surrender Roman territory without a contest, war was at once declared.  His immediate adversaries were of no great account, being, as they were, the petty kings of Osrhoene, Adiabene, and Hatra; but behind them loomed the massive form of the Parthian State, which was attacked through them, and could not be indifferent to their fortunes.

In the spring of A.D. 195, Severus, at the head of his troops, crossed the Euphrates in person, and taking up his own quarters at Nisibis, which the Mesopotamians had been unable to capture, proceeded to employ his generals in the reduction of the rebels and the castigation of their aiders and abettors.  Though his men suffered considerably from the scarcity and badness of the water, yet he seems to have found no great difficulty in reducing Mesopotamia once more into subjection.  Having brought it completely under, and formally made Nisibis the capital, at the same time raising it to the dignified position of a Roman colony, he caused his troops to cross the Tigris into Adiabene, and, though the inhabitants offered a stout resistance, succeeded in making himself master of the country.  The Parthian monarch seems to have made no effort to prevent the occupation of this province.  He stood probably on the defensive, expecting to be attacked, in or near his capital.  But Severus could not afford to remain in these remote regions.  He had still a rival in the West in the person of Clodius Albinus, who might be expected to descend upon Italy, if it were left exposed to his attacks much longer.  He therefore quitted the East early in A.D. 196, and returned to Rome with all speed, leaving Parthia very insufficiently chastised, and his new conquests very incompletely settled.

Scarcely was he gone when the war broke out with greater violence than ever.  Volagases took the offensive, recovered Adiabene, and crossing the Tigris into Mesopotamia, swept the Romans from the open country.  Nisibis alone, which two years before had defied all the efforts of the Mesopotamians, held out against him, and even this stronghold was within a little of being taken.  According to one writer, the triumphant Parthians even crossed the Euphrates, and once more spread themselves over the fertile plains of Syria.  Severus was forced in A.D. 197 to make a second Eastern expedition to recover his lost glory and justify the titles which he had taken.  On his first arrival in Syria, he contented himself with expelling the Parthians from the province, nor was it till late in the year, that, having first made ample preparation, he crossed the Euphrates into Mesopotamia.