It is indeed possible that the beginnings of Chinese civilization can be traced even farther back than to the times when we find something more than barbarism in the valley of the Wei. Notice that at the north-west corner of the high plateau of Tibet huge mountains make a great curve round to the Thian-Shan, enclosing a bay of the lower plateau shut off from all else on north west and south by high lands and on the east by the desert. The great height of the surrounding mountains squeezes yet some moisture from the dry air, so that round their bases is a series of oases of great fertility. If protection counts for anything, it is in just such a situation that we should expect to find the beginnings of a civilization. It is possible, perhaps even probable, that the beginnings of distinctively Chinese civilization are due to those who found their way thence under the curtain of the mountains bordering Tibet on the north, to what was to them the much more desirable valley of the Wei.
But this was not the only occasion, if it was an occasion, on which the plateau peoples descended to the plain, and other invaders were rather nomads of the steppe than settled agriculturists, so that they were felt to be a menace, as is seen in the existence of the wall. At the same time, the incursions of such hardy races were not without advantage. It is probably not alone owing to their colder climate that the peoples of the Hwang-Ho are a sturdier race than are those of the south. It is they who have had to bear the brunt of attacks, and who have benefited to the greater extent by the addition of new blood; some of the intermixture may have been at first during war time, but probably some has taken place during times of peace, and even plateau tribes, which have entered the land as conquerors, have in the end been absorbed into the general stock.
It was about 100 B.C. when the Chinese, recognizing that the best defence is attack, first succeeded in extending their rule, if but for a short time, over the inhabitants of the plateau. At the break-up of the Han power we have seen that there was a certain disruption, and in this, as was natural, the control of the plateau was lost. When China did at length, shortly after A.D. 600, settle down under the powerful rule of the Tang Dynasty, it was also but natural that another attempt should be made to extend its borders still farther. On both occasions the chief objective was the Tarim basin, and on both occasions the influence of the intervening distance across all but impassable deserts was too strong to allow the rule to be more than nominal or to last for long. The occasions are, however, noteworthy, for the Chinese then made a contact, however slight, with the Western nations from whom they were separated by the great breadth of the plateau and the great plain, and yet more by the peoples on them.
Before considering the last and in some respects the greatest influence exerted by the plateau, we must consider an allied phenomenon. We have seen that in Europe a civilized centre is apt to rouse to action some neighbouring centre less civilized if more forceful; we have now to notice a similar fact in the case of China. Manchuria lies to the north, separated from China by the deeply cut Gulf of Pe-chi-li, which allows only a narrow neck of land to intervene between its western end and the plateau edge. Lying farther north, Manchuria is a colder land and altogether less desirable for an early civilization than China. Here, however, men lived, and in course of time they were roused to action by the neighbouring civilization, though the geographical con ditions separated them sufficiently to allow them to feel and be independent. A tribe of these Manchus— the Kitan Tatars—extended their rule southwards, so that by A.D. 900 we find a semi-alien power occupying the north of what had been China. These Tatars never dominated much of the country, but so much did they strike the imagination of the few travellers who found their way from the west, that it is from their name we get the mediaeval name of China—" Cathay." This wakening of Manchuria was a new feature in Chinese history, and its newness was marked by the fact that it was now that Pekin was founded. Before this time the capital of China had lain, now here, now there, in the valley of the Wei or Middle Hwang-Ho. Hence forward, with a break for but a short time, it is from Pekin that China is governed. Notice the significance of its position within, but just within, the northern plain, at the exit of the narrow way from Manchuria, between the highlands of the west and the Gulf of Pe-chi-li on the east : a centre for the organization of the land from a Manchurian base, as Vienna is a centre from which the Austrians could organize Hungary, as London is a centre from which those who came from the opposite shores of Europe could organize England, as Edinburgh is the centre from which those who came from England could organize Scotland, or as Dublin is the centre from which those who crossed from Anglesea could organize Ireland. Awakened Manchuria sent yet another horde to replace the first, and to dominate yet more of China, while distinctively Chinese power was forced farther and farther south till it held only the Yangtse and Si-Kiang basins—the hilly regions.