"One must not think of a nomadic stage as a predecessor of a settled stage in human affairs. To begin with, man was a slow drifter, following food. Then one sort of men began to settle down, and another sort became more distinctly nomadic. The settled sort began to rely more and more upon grain for food; the nomad began to make a greater use of milk for food. He bred his cows for milk. The two ways of life specialized in opposite directions. It was inevitable that nomad folk and the settled folk should clash, that the nomads should seem hard barbarians to the settled peoples, and the settled peoples soft and effeminate and very good plunder to the nomad peoples. Along the fringes of the developing civilizations there must have been a constant raiding and bickering between hardy nomad tribes and mountain tribes and the more numerous and less warlike peoples in the towns and villages. For the most part this was a mere raiding of the borders. The settled folk had the weight of numbers on their side; the herdsmen might raid and loot, but they could not stay. That sort of mutual friction might go on for many generations. But ever and again we find some leader or some tribe amidst the disorder of free and independent nomads, powerful enough to force a sort of unity upon its kindred tribes, and then woe betide the nearest civilization. Down pour the united nomads on the unwarlike, unarmed plains, and there ensues a war of conquest. Instead of carrying off the booty, the conquerors settle down on the conquered land, which becomes all booty for them; the villagers and townsmen are reduced to servitude and tribute paying, they become hewers of wood and drawers of water, and the leaders of the nomads become kings and princes, masters and aristocrats. They, too, settle down, they learn many of the arts and refinements of the conquered, they cease to be lean and hungry, but for many generations they retain traces of their old nomadic habits, they hunt and indulge in open-air sports, they drive and race chariots, they regard work, especially agricultural work, as the lot of an inferior race and class. This in a thousand variations has been one of the main stories in history for the last seventy centuries or more. In the first history that we can clearly decipher we find already in all the civilized regions a distinction between a non-working ruler class and the working mass of the population. And we find, too, that after some generations, the aristocrat, having settled down, begins to respect the arts and refinements and law-abidingness, of settlement, and to lose something of his original hardihood. He intermarries, he patches up a sort of toleration between conqueror and conquered; he exchanges religious ideas and learns the lessons upon which soil and climate insist. He becomes a part of the civilization he has captured; and as he does so, events gather towards a, fresh invasion by the free adventurers of the outer world."