During his last months, however, a new threat was growing to the rising power of Parthia, and this was to become the chief preoccupation of his immediate successors. Disturbances along the area of the Chinese frontier had set on foot a large-scale westward migration in Central Asia. The powerful tribal confederation of the Yueh-chi, apparently identical with that known to the classical writers as the Tochari, had been attacked by their Altaic neighbours the Hsiung-nu (ancestors, it seems, of the later Huns), and driven pell-mell from their grazing-grounds in Kansu province. The Yueh-chi emigrated westwards, probably by way of Turfan and Qarashahr, and along the Hi River. In the course of their march they collided from time to time with another formidable horde, the Wu-sun, who may have been identical with the Issedones mentioned by Herodotus and other classical writers. Finally, passing Lake Issik Kol, the Yueh-chih emerged from the mountains once more onto the steppe, defeating and driving before them the Saka tribes who had pastured there since the days of the Achaemenian empire. These Saka peoples seem to have been of eastern Iranian speech, and may well have included ancestors of the Afghans, the present-day speakers of Pashto. Thus it came about that the displaced Sacae, of whom the group most prominently mentioned was that of the Sacaraucae (Saka rawaka), began to impinge on the Parthian boundaries early in the reign of Phraates II. They may indeed have already appeared in the last days of Mithradates I. Yet before matters reached a crisis on the eastern frontier of Parthia. In Syria, the usurper Tryphon continued to rule over the greater part of the country, with his main strength in Apamea and in Antioch. Cleopatra, daughter of Ptolemy Philometor of Egypt, who had been married to Demetrius II who was now captive, held out in Seleucia-inPieria on the Syrian coast. Despairing of making headway alone against the usurper, she called in her brother-in-law Antiochus, the younger son of Demetrius Soter who had been brought up at Side, and offered him her hand. Thus Antiochus was acclaimed king, becoming known to historians as Antiochus VII Sidetes.
Formation of Ancient Persian State: World Superpower
