On other frontiers also Trajan strengthened or extended the boundaries of the empire. In 106 he annexed the kingdom of the Nabataean Arabs to the east of Palestine and Syria. From this was formed the province of Arabia. In Africa also the Romans occupied new territory, and secured it against Berber raids by creating new fortresses at Lambaesis and Timgad.
*The Parthian war, 114-116 A. D.* The peaceful relations which had existed between Rome and Parthia since the time of Nero were broken in 114 A. D. when the Parthian king Chosroes drove out the Armenian ruler, who had received his crown from Trajan's hands, and set his own son Parthamasiris in his stead. Trajan at once repaired to the East and concentrated an army for the invasion of Armenia. Parthamasiris offered to acknowledge the Roman suzerainty over Armenia, but Trajan determined to effect a definite settlement of the eastern frontier by the permanent occupation of Armenia and, for strategic reasons, of Mesopotamia also. In 114 he effected an easy conquest of Armenia, and in the next year annexed Upper Mesopotamia. He now resolved to complete his success by the overthrow of the Parthian kingdom. Accordingly, in 116 A. D., he overran Assyria and made it a province, and then pressed on to the Persian gulf, capturing Seleucia, Babylon and the Parthian capital Ctesiphon on his way. From dreams of further conquests Trajan was recalled by a serious revolt in Mesopotamia which was only subdued with great effort, and in 117 A. D. Chosroes was able to reoccupy his capital. At the same time the eastern provinces were disturbed by a rising of the Jews, which began in Cyrene in 115 A. D. and spread to Cyprus, Egypt and Mesopotamia. Horrible massacres were perpetrated both by the Jews and their enemies, and large numbers of troops had to be employed before order was restored.
News of revolts in Africa and Britain, and of troubles on the Danubian border, led Trajan to set out for Rome. On the way he fell ill and died at Selinus in Cilicia on 8 August, 117 A. D.
*Hadrian princeps.* Trajan left no male heir and had associated no one with himself in the _imperium_ or tribunician power. However, on his deathbed he adopted his cousin and one-time ward, Publius Aelius Hadrianus, also a native of Italica. Hadrian was married to Sabina, a grand-daughter of Trajan's sister Marciana. He had had a distinguished military career and in 117 A. D. was commander of the army in Syria. At the news of his adoption his troops saluted him as Imperator and his nomination was confirmed by the Senate. The only opposition came from some of the ablest of Trajan's officers, notably Lusius Quietus, who soon plotted against his life. But their conspiracy was detected and the Senate condemned to death the four leaders in the plot.