"Snowy Mountains," where travellers are exposed to the attacks of the "dragons," those mystic animals which may possibly symbolize nothing more than the sufferings entailed by snow and ice. Like the other Buddhist pilgrims of this epoch, H'wen-Tsang skirted the Tibetan plateaux, where the Buddhist religion had only just been introduced, and reached India through the Oxus valley and Afghanistan. But some twenty years after his return, in 667 or 668, Chinese armies had already traversed Tibet and Nepal, thus penetrating directly into India, where they captured over six hundred towns. At this time the Chinese Empire comprised, with the tributary states, not only the whole depression of Eastern Asia, but also all the outer slopes of the highlands and plateaux surrounding it as far as the Caspian. It was also during this period that the Nestorian missionaries introduced Christianity into the empire.
| Fig. 1.—Itinerary of H'wen-Tsang. | ||||
| Scale 1 : 30,000,000. | ||||
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| 0 to 10,000 Feet. | 10,000 to 16,500 Feet. | 16,500 Feet and upwards. | ||
 600 Miles.
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The progress of Islam in the west of Asia and along the shores of the Mediterranean necessarily isolated China, and long rendered all communication with Europe impossible. But in the northern regions of the Mongolian steppes warlike tribes were already preparing for conquest, and thanks to their triumphant march westwards to the Dnieper, they opened up fresh routes for explorers across the whole of the Old World. In order to protect themselves from these northern children of
