INTRODUCTION TO SOCIOLOGY 533
Assyria and Chaldea. The three powers touched each other. Their great rivers connected them with the sea. Assyria commanded the heights, the sources; the Chaldeans, the plain and mouths of the Tigris and Euphrates; and by the latter and the Gulf of Persia all these peoples, embraced in the same movement, were connected with the sea,
The eastern coast of the Mediterranean between Egypt and Assyria became the zone of contention. Protected by the moun- tains, Phoenicia for a long time was able to maintain itself along this coast and to develop by sending out its merchants into Asia, into the islands of the Mediterranean, and along the Greek coast.
All the while, as we see, the tribes or principalities or inde- pendent kingdoms were absorbed by one or another empire, their frontiers were transformed, and they became the bases of internal administrative divisions, even for religious purposes. Further- more, in proportion as the general frontiers became more distant, the internal machinery of administration became specialized and complicated. Among the incorporated populations the external frontiers of the original groups were removed, even between the different classes, for the sake of substituting therefor a strong military organization, administrators and praetors, under a supreme head. That the military and political boundaries must be displaced before a relative peace can be established in the interior, the great Roman peace was an example such as humanity has not presented since.
I now call attention again to an important phenomenon. It is that great intersocial agitations are produced especially in the frontier zones, which are not only military zones, but also zones of commerce, of products, and of interchange of ideas between peoples. In the military phase of civilizations these frontier zones naturally tend to take on also a military character. But we have seen that the desert is the most powerful of obstacles. The oceans, interior seas, great rivers, lakes, and creeks first cease to present themselves as obstacles. Each military state will there- fore tend to make its frontier zone a military zone, and the best means will be by transforming this zone into a desert, or arti- ficially fortifying it by concentrating there its principal military
