Tibet. Beyond China Proper are continental and insular border areas that had periodically been incorporated into Chinese empires from 617 to 1644. These areas include Tibet, Xinjiang, Mongolia, and Manchuria. Derived from a Mongolian term, the name Tibet was used in Europe by the thirteenth century. A mountainous area, Tibet covers about 500,000 square miles, half of which is more than 15,000 feet in altitude. The source of the principal Chinese and Asian rivers, Tibet had a population of about two million during the period under consideration. Agricultural and mineral resources were insignificant. Chinese interest in Tibet began in 650 when a military expedition occupied Lhasa, the capital. In the thirteenth century the Mongols incorporated Tibet into their empire, and Kublai Khan established a regime in Tibet under the control of priestkings. After the Mongols, Ming rulers from time to time tried to reincorporate Tibet into their domains.

Xinjiang. Called...