Then he began his return to Syria by the route along which he had come, detained on the way by a vain attack on the Arabs in Hatra, the residence of the king of the brave tribes of the Mesopotamian desert, whose mighty works of fortification and magnificent buildings are still at the present day imposing in their ruins. He intended to continue the war next year, and so to make the subjection of the Parthians a reality. But the combat in the desert of Hatra, in which the sixty-year-old emperor had bravely fought with the Arab horsemen, was to be his last. He sickened and died on the journey home (8th Aug. 117), without being able to complete his victory and to hold the celebration of it in Rome; it was in keeping with his spirit that even after death the honour of a triumph was accorded to him, and hence he is the only one of the deified Roman emperors who even as god still bears the title of victory. [Sidenote: Trajan’s Oriental policy.] Trajan had not sought war with the Parthians, but it had been forced upon him; not he, but Chosroes had broken the agreement as to Armenia, which during the last forty years had been the basis of the state of peace in the region of the Euphrates. If it is intelligible that the Parthians did not acquiesce in it, since the continuing suzerainty of the Romans over Armenia carried in itself the stimulus to revolt, we must on the other hand acknowledge that in the way hitherto followed further steps could not be taken than were taken by Corbulo; the unconditional renunciation of Armenia, and--which was the necessary consequence of it--the recognition of the Parthian state on a footing of full equality, lay indeed beyond the horizon of Roman policy as much as the abolition of slavery and similar ideas that could not be thought of at that time. But if permanent peace could not be attained by this alternative, there was left in the great dilemma of Roman Oriental policy only the other course--the extension of direct Roman rule to the left bank of the Euphrates. Therefore Armenia now became a Roman province, and no less Mesopotamia. This was only in keeping with the nature of the case. The conversion of Armenia from a Roman vassal-state with a Roman garrison into a Roman governorship made not much change externally; the Parthians could only be effectively ejected from Armenia when they lost possession of the neighbouring region; and above all, the Roman rule as well as the Roman provincial constitution found a far more favourable soil in the half-Greek Mesopotamia than in the thoroughly Oriental Armenia. Other considerations fell to be added. The Roman customs-frontier in Syria was badly constituted, and to get the international traffic from the great commercial marts of Syria towards the Euphrates and the Tigris entirely into its power was an essential gain to the Roman state, as indeed Trajan immediately set to work to institute the new customs-dues at the Euphrates and Tigris.[52]