The first two centres of civilisation are found in the valley of the Nile and the valley of the Tigris and Euphrates; the civilisations of Egypt and Babylon, the oldest in the world. There is, however, a good deal of evidence by which we may bring these civilisations nearer to each other in their earliest stages, so that we must not confidently speak of two quite independent civilisations. The civilisation which developed on the Euphrates is found first at Susa, on the hills overlooking the plains of Mesopotamia, about 6000 B.C. A people akin to the Turkish or Chinese lives among the hills, and makes the vague advance from higher Neolithic culture to primitive civilisation. About the same time the historical or dynastic civilisation begins in Egypt, and some high authorities, such as Mr. Flinders Petrie, believe that the evidence suggests that the founders of this dynastic civilisation came from "the mountainous region between Egypt and the Red Sea." From the northern part of the same region, we saw, the ancestors of the Chinese set out across Asia. We have here a very suggestive set of facts in connection with early civilisation. The Syro-Arabian region seems to have been a thickly populated centre of advancing tribes, which would be in striking accord with the view of progress that I am following. But we need not press the disputed and obscure theory of the origin of the historic Egyptians. The remains are said to show that the lower valley of the Nile, which must have been but recently formed by the river's annual deposit of mud, was a theatre of contending tribes from about 8000 to 6000 B.C. The fertile lands that had thus been provided attracted tribes from east, west, and south, and there is a great confusion of primitive cultures on its soil. It is not certain that the race which eventually conquered and founded the historical dynasties came from the mountainous lands to the east. It is enough for us to know that the whole region fermented with jostling peoples. Why it did so the previous chapters will explain. It is the temperate zone into which men had been pressed by the northern ice-sheet, and from Egypt to the Indian Ocean it remained a fertile breeding-ground of nations.