"But historical development does not rest on the tendency towards civilisation alone. It arises also from impulses of a very different kind, especially from the rivalry of nations engaged in conflict with each other for the possession of the soil or for political supremacy. It is in and through this conflict, affecting as it does all the domain of culture, that the great empires of history are formed. In their unceasing struggle for dominion the peculiar characteristics of each nation are modified by universal tendencies, but at the same time resist and react upon them."