When emperors ruled China, those men often wanted to be seen as benevolent—embracing every kind of beauty under heaven. To do this, the emperors encouraged minorities to stay where they had lived for centuries if not millennia. Even in Tibet, China has not driven out or slaughtered in mass (http://wp.me/pN4pY-6S) the minorities as Europeans did to North American natives, who lived off that land for more than ten thousand years.
History shows that the Chinese emperors did not force minorities from their land with false promises followed by broken treaties. In China, if a minority king proposed a marriage alliance with the Emperor, the Emperor adopted a Chinese beauty as his daughter and sent her to the minority king. This is portrayed in The Dream of Red Mansions, a Chinese classic written in the 18th century.