(Coreans), who first appear on the upper Yalu about the Christian era, established themselves in Liaotung. While paying tribute to China they succeeded in maintaining a virtually independent kingdom, extending as far west as the Liao, and having its capital at Pingyang, until in a.d. 668 they were overthrown by the Tang dynasty. Their name still remains attached to many villages in Fengtien, and any ruins whose history is lost are ascribed by the popular voice to the Kaoli. It was not till the tenth century that they revived sufficiently to establish the modern Corean kingdom, since when the Yalu has remained the boundary on the west.
Meanwhile Central Manchuria had been following an independent course under the headship of various tribes of whom little is known but the name. The fall of the Corean power was the occasion of the rise of a powerful confederacy named Bohai, which from its capital near Ninguta dominated the country from the Sungari almost to the mouth of the Yalu. During this period the country was prosperous and well peopled. "Learning flourished"—presumably Chinese learning. However, in 926 the power of Bohai was destroyed by the invasion of the Kitan, a race dwelling on the upper Liao, who for many centuries had raided the north of China, and who now turned their arms eastwards, overrunning the country as far as the Hurka. It was this people who at the same time established the Liao dynasty in North China. From them the name Cathay was carried to Europe, and China is still known to Russia as Kitai.
The people of Central Manchuria now appear under the name of Nüchen, but broken up into many independent clans. Under the weight of disaster, their former civilisation was lost, and they reverted to the nomadic state. In 1114 a Nüchen chief attacked an army of the Liao on the banks of the Sungari, where his victory began a career of conquest more startling in its rapidity than even that of the later Manchus, for in nine years he had swept down through Manchuria and taken Peking, thus founding the dynasty of Kin.
