OSROENE or OSRHOENE, a district of northwestern Mesopotamia, in the hill country on the upper Bilechas (Belichus; mod. Nahr Belik, Bilikh), the tributary of the Euphrates, with its capital at Edessa (q.v.), founded by Seleucus I. About 130 B.C. Edessa was occupied by a nomadic Arabic tribe, the Orrhoei (Plin. v. 85; vi. 25, 117, 129), who founded a small state ruled by their chieftains with the title of kings. After them the district was called Orrhoene (thus in the inscriptions, in Pliny and Dio Cassius), which occasionally has been changed into Osroene, in assimilation to the Parthian name Osroes or Chosroes (Khosrau). The founder of the dynasty is therefore called Osroes by Procop. (Bell Pers. i. 17) but Orhai or Urhai, son of Hewyd (i.e. "the snake"), in the chronicle of Dionysius of Tellmahre ; he is no historical personality, but the eponym of the tribe. The kings soon became dependants of the Parthians; their names are mostly Arabic (Bekr, Abgar, Mdnu), but among them occur some Iranian (Parthian) names, as Pacorus and Phratamaspates. Under Tigranes of Armenia they became his vassals, and after the victories of Lucullus and Pompey, vassals of the Romans. Their names occur in all wars between Romans and Parthians, when they generally inclined to the Parthian side; e.g., in the wars of Crassus and Trajan. Trajan deposed the dynasty, but Hadrian restored it. The kings generally used Greek inscriptions on their coins, but when they sided with the Par thians, as in the war of Marcus Aurelius and Verus (A.D. 161
165), an Aramaic legend appears instead. Hellenism soon dis appeared and the Arabs adopted the language and civilization of the Aramaeans. This development was hastened by the introduc tion of Christianity, which is said to have been brought here by the apostle Judas, the brother of James, whose tomb was shown in Edessa. In 190 and 201 we hear of Christian churches in Edessa. King Abgar IX. (or VIII.) (179-214) himself became a Christian and abolished the pagan cults, especially the rite of castration in the service of Atargatis, which was now punished by the loss of the hands.
Caracalla in 216 abolished the kingdom of Osroene (Dio Cass. 77. 14) and Edessa became a Roman colony. The list of the kings of Osroene is preserved in the Syrian_ chronicle of Dionysius of Tellmahre, which is checked by the coins and the data of the Greek and Roman authors ; it has been reconstructed by A. v. Gutschmid, "Untersuchungen fiber die Geschichte des Konig reichs Osroene," in Memoires de l'Acad. de St. Petersbourg, t. xxxv. (1887). Edessa remained Roman till it was taken by Chosroes II. in 6o8; but in 625 Heraclius conquered it again. In 638 it was taken by the Arabs. (ED. M.) OSSA (mod. Kissovo, Kissavo), a mountain (el. c. 6,400 ft.) in Larissa, S.E. part of Thessaly, Greece; S. of Olympus, from which it is separated by the valley of Tempe, and N. of Pelion which the Giants are said to have piled on it to scale Olympus.