Even less is known of the early days of Yen than is known of Ts'in, Tsin, and Ts'i; there is not even a vague tradition to suggest who ruled it, or what sort of a place it was, before the Chou prince was sent there; all that is anywhere recorded is that it was a very small, poor, and feeble region, dovetailed in between Tsin and Ts'i, and exposed north to the harassing attacks of savages and Coreans (_i.e._ tribes afterwards enumerated as forming part of Corea when the name of Corea became known). The mysterious region is only mentioned here at all on account of its distinguished origin, in order to show that the Chinese cultivators had from the very earliest times apparently succeeded in keeping the bulk of the Tartars to the left bank of the Yellow River all the way from the Desert to the sea; because later on (350 B.C.) Yen actually did become a powerful state; and finally, because if any very early notions concerning Corea and Japanese islands had ever crept vaguely into China at all, it must have been through this state of Yen, which was coterminous with Liao Tung and Manchuria. The great point to remember is, the extensive territory between the Great Wall and the Yellow River then lay almost entirely beyond the pale of ancient China, and it was only when Ts'in, Tsin, Ts'i, and Yen had to look elsewhere than to the Emperor for protection from Tartar inroads that the centre of political gravity was changed once and for ever from the centre of China to the north. We know nothing of the precise causes which conduced to unusual Tartar activity at the dawn of Chinese true history: in the absence of any Tartar knowledge of writing, it seems impossible now that we ever can know it. Still less are we in a position to speculate profitably how far the movements on the Chinese frontier, in 800-600 B.C., may be connected with similar restlessness on the Persian and Greek frontiers, of which, again, we know nothing very illuminating or specific. It is certain that the Chinese had no conception of a Tartar empire, or of a coherent monarchy, under the vigorous dominion of a great military genius, until at least five centuries after the Tartars, killed a Chinese Emperor in battle as related (771 B.C.). It is even uncertain what were the main race distinctions of the nomad aggregations, loosely styled by us "Tartars," for the simple reason that the ambiguous Chinese terminology does not enable us to select a more specific word. Nevertheless, the Chinese do make certain distinctions; and, as what remains of aboriginal populations in the north, south, east, and west of China points strongly to the probability of populations in the main occupying the same sites that they did 3000 years ago (unless where specific facts point to a contrary conclusion), we may fairly assume that the distribution was then very much as now-beginning from the east, (1) Japanese, (2) Corean, (3) Tungusic, (4) Mongol-Turkish, (5) Turkish, (6)