Historical accounts have recorded, for instance, that stone implements were still in use in Manchuria and eastern Mongolia at a time when metal was known and used in western Mongolia and northern China.

Claim to the Chinese imperial throne The Kitan, a league of tribes under the leadership of an apparently Mongol tribe, had grown steadily stronger in north-eastern Mongolia during the T'ang epoch.

The emperor and his entourage could return to Mongolia in the summer, when China became too hot or too humid for them; and from Peking they were able to maintain contact with the rest of the Mongol empire.

CHINA, THE GREAT WALL OF, a wall, with towers and forts at intervals, about 2000 m. long, from 20 to 30 ft. high, and 25 ft. broad, which separates China from Mongolia on the N., and traverses high hills and deep valleys in its winding course.

All that we know indicates that at the time of the Peking Man there must have been a warmer and especially a damper climate in North China and Inner Mongolia than today.

The reinforcements for these campaigns, and for the garrisons which in the following decades were stationed in the Ili region and in the west of eastern Turkestan, marched along the road from Peking that leads northward through Mongolia to the far distant Uliassutai and Kobdo.