THE SCIENCE OF HISTORY
of the other peoples. All the types of ancient culture evolved their special structural characteristics and differentiated themselves into separate sociopolitical crystals by influencing and modifying one another, and hence may be looked upon as more or less the joint-products of certain systems of world-forces.
The kaleidoscopic changes that marked the state-systems of the Middle Ages were likewise due to the stir and turmoil produced by social and political intercourse of peoples with one another. Those very barbaric races who had during the preceding epochs excited the military ambition of the established powers, whose very existence had, in fact, taxed the strategic ability of the rulers of the border-lands and frontier-provinces,
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