The other external force which contributed to this inglorious end of a voyage begun with such fair promise was set in motion from the Farthest East. I do not reckon it in this account that the Parthians again rebelled and in 140 B.C. advanced their western frontier to the Euphrates, thus forming the philhellen kingdom of west Iran which grew behind the breastwork of the Seleucid empire to such power that later it disputed with some success Rome's claim to suzerainty in Asia. Nor do I enter it here that Armenia established its complete independence, and under Tigranes the Great annexed for a time (83-69 B.C.) all of the Seleucid realm then remaining. For these are internal movements analogous to the insurrection of the Jews. It was from the banks of the Hoang-Ho that an advance toward the west occurred in the early part of the second century B.C. which may be paralleled with the simultaneous advance eastward of the Roman power from the banks of the Tiber.[104] The oncoming Eastern assailant was the conglomerate of Indo-European peoples whom the Chinese call the Yue Tchi. They came along the edges of the great desert of shifting sand in Eastern Turkestan down which flows the mouthless Tarim River, not with the _élan_ of conquerors, but retreating slowly before the superior strength of the Huns (Hioung Nou), their former subjects, with whom they had recently fought an unsuccessful war for the possession of North China. It was against their conquerors, we may remark in passing, that the Chinese emperors, Chi-Houang-ti and Wou-ti of the Ts'in and Han Dynasties respectively, constructed in the third and second centuries B.C., to the south of the Desert of Gobi, the great Chinese _Limes_, or Wall. In 159 B.C. the Yue Tchi occupied Sogdiana. Twenty years later (139 B.C.) they crushed the Greek kingdom of Bactria; so that in this general region it was only in India, in the vast district drained by the Indus River, that Greek kingdoms existed thereafter. Somewhere near the opening of the Christian era these, too, succumbed to the Yue Tchi, now properly designated Indo-Scythians by the Greeks. For several centuries the Indo-Scythians, like the Huns who followed them in the fifth century of our era, and the Turks who followed the Huns in the sixth, kept open the trade routes along which they had themselves advanced when driven westward from the Hoang-Ho. Their successors transmitted to the frontiers of China Manichæism, the cosmopolitan religion of Iran: _they_ did a greater work. They not only forwarded Buddhism to the Chinese; but before it, and with it, the pure as well as the debased art of Greece. Among the priceless treasures which Dr. Stein has brought back from the desert cities of Cathay, none are more remarkable than certain clay seals attached to documents of the third century of our era, found at Niya in a district then under Chinese control;[105] for one of them might have been made for Diodotus, the first Greek