After the death of this versatile monarch, little is heard of Edessa till A.D. 115, when the Emperor Trajan established himself there, in preparation for an invasion of Parthia. Edessa was a convenient spot for such a step, being within easy reach of the Mediterranean _via_ Aleppo, and commanding the road from Syria to the East. Having prepared his army, he set out southwards; but while he subdued southern Mesopotamia, the reigning Abgarus, taking an advantage of Trajan’s absence, promptly rebelled, and ejected the Roman garrison installed in the citadel, whose ramparts and walls still stand on the southern side of the city. Vengeance overtook this effort at independence, for during the next year (A.D. 116), Lucius Quietus, a Roman general, captured the place and burnt it. Yet once more we hear of Edessa before it sinks into the temporary obscurity that followed the fall of the Roman power in Mesopotamia. In one of the last attempts of Rome finally to crush the Parthians (A.D. 197), Severus, who came from France to try and recover the territories (Edessa among them) recently conquered by Vologases V. of Parthia, found Edessa on his way to the East, and the reigning Abgarus, always ready to turn a complacent face to the man in power, submitted without a murmur, and handed over his sons to the Romans as hostages. It was not perhaps remarkable that Edessa, after these centuries of strife between the great empires, that saw the ebbing and flowing tide of Assyrian, Persian, Greek, Roman and Parthian, Roman and Arab, sweep by and over it, possessed a population of which the Roman and Greek element, particularly the latter, was an important section. When Christianity began to spread, the proximity of Edessa to Antioch made it easy for the bishops of those early days to travel there, and so we find as a result of the efforts of converts a college springing up in very early times. Though there were doubtless many of the Greeks in this college, we are told that it was the Chaldeans who founded it, and made it famous for its erudition, and particularly its knowledge of the medical science. Doubtless Chaldean, Greek, and Arabic were all spoken there; the last certainly, for Arab pupils of the college, natives of the land towards Mecca and Medina, were relations of the early Muhammadan saints, notably Abu Bekr. This famous school was dissolved by Zeno the Isaurian,[5] and the Chaldeans, with no loss of zeal, transferred it to Susa, in Khuzistan of south-west Persia, whence the now famous missionaries of the Chaldeans to China were despatched.