Chapter IX · THE EUPHRATES FRONTIER AND THE PARTHIANS. (continued 3)

Persian war of Carus.The ephemeral kingdom of Palmyra was in its origin as in its fall closely bound up with the relations of the Romans to the non-Roman East, but not less a part of the general history of the empire. For, like the western empire of Postumus, the eastern empire of Zenobia was one of those masses into which the mighty whole seemed then about to resolve itself. If during its subsistence its leaders endeavoured earnestly to set limits to the onset of the Persians, and indeed the development of its power was dependent on that very fact, not merely did it in its collapse seek deliverance from those same Persians, but probably in consequence of the revolt of Zenobia Armenia and Mesopotamia were lost to the Romans, and after the subjugation of Palmyra the Euphrates again for a time formed the frontier. The queen, when she arrived at it, hoped to find a reception among the Persians; and Aurelian omitted to lead the legions over it, seeing that Gaul, along with Spain and Britain, still at that time refused to recognise the government. He and his successor Probus were not able to take up this struggle. But when in the year 282, after the premature end of the latter, the troops proclaimed the commander next in rank, Marcus Aurelius Carus, as emperor, it was the first saying of the new ruler that the Persians should remember this choice, and he kept it. Immediately he advanced with the army into Armenia and re-established the earlier order there. At the frontier of the land he was met by Persian envoys, who declared themselves ready to grant all that was reasonable;117 but they were hardly listened to, and the march went on incessantly. Mesopotamia too became once more Roman, and the Parthian residential cities Seleucia and Ctesiphon were again occupied by the Romans without encountering lengthened resistance—to which the war between brothers then raging in the Persian empire contributed its part.118 The emperor had just crossed the Tigris, and was on the point of penetrating into the heart of the enemy’s country, when he met his death by violence, presumably by the hand of an assassin, and thereby the campaign also met its end. But his successor obtained in peace the cession of Armenia and Mesopotamia;119 although Carus wore the purple little more than a year, he re-established the imperial frontier of Severus.

Persian war under Diocletian.Some years afterwards (293) a new ruler, Narseh, son of king Shapur, ascended the throne of Ctesiphon, and declared war on the Romans in the year 296 for the possession of Mesopotamia and Armenia.120 Diocletian, who then had the supreme conduct of the empire generally, and of the East in particular, entrusted the management of the war to his imperial colleague Galerius Maximianus, a rough but brave general. The beginning was unfavourable. The Persians invaded Mesopotamia and reached as far as Carrhae; the Caesar led against them the Syrian legions over the Euphrates at Nicephorium; between these two positions the armies encountered each other, and the far weaker Roman force gave way. It was a hard blow, and the young general had to submit to severe reproaches, but he did not despair. For the next campaign reinforcements were brought up from the whole empire, and both rulers personally took the field; Diocletian took his position in Mesopotamia with the chief force, while Galerius, reinforced by the flower of the Illyrian troops that had in the meantime come up, met, with a force of 25,000 men, the enemy in Armenia, and inflicted on him a decisive defeat. The camp and the treasure, nay, even the harem, of the great-king fell into the hands of the warriors, and with difficulty Narseh himself escaped from capture. In order to recover the women and the children the king declared himself ready to conclude peace on any terms; his envoy Apharban conjured the Romans to spare the Persians, saying that the two empires, the Roman and the Parthian, were, as it were, the two eyes of the world, and neither could dispense with the other. It would have lain in the power of the Romans to add one more to their Oriental provinces; the prudent ruler contented himself with regulating the state of possession in the north-east. Mesopotamia remained, as a matter of course, in the Roman possession; the important commercial intercourse with the neighbouring foreign land was placed under strict state-control and essentially directed to the strong city of Nisibis, the basis of the Roman frontier-guard in eastern Mesopotamia. The Tigris was recognised as boundary of the direct Roman rule, to such an extent, however, that the whole of southern Armenia as far as the lake Thospitis (lake of Van) and the Euphrates, and so the whole upper valley of the Tigris, should belong to the Roman empire. This region lying in front of Mesopotamia did not become a province proper, but was administered after the previous fashion as the Roman satrapy of Sophene. Some decades later the strong fortress of Amida (Diarbekir) was constructed here, thenceforth the chief stronghold of the Romans in the region of the upper Tigris. At the same time the frontier between Armenia and Media was regulated afresh, and the supremacy of Rome over that land, as over Iberia, was once more confirmed. The peace did not impose important cessions of territory on the conquered, but it established a frontier favourable to the Romans, which for a considerable time served in these much contested regions as a demarcation of the two empires.121 The policy of Trajan thereby obtained its complete accomplishment; at all events the centre of gravity of the Roman rule shifted itself just at this time from the West to the East.