Page:A General Sketch of Political History from the Earlist Times.djvu/102

 9o THE GLORY OF GREECE AND RISE OF ROME about i ioo B.C. to 250 B.C. It was then displaced by one of the great vassals who founded the brief Chin dynasty, broke up the feudal system, and built the Great Wall which became a permanent barrier against the incursions of barbarian tribes from Central Asia. Western Europe was overrun by a Celtic invasion, of which a re- turning wave seems to have rolled back along the Mediterranean, establishing the Gauls in North Italy during the fourth century, touching Greece in the third, and finally subsiding in Asia Minor.