The Cambridge History of India, Vol. I: Ancient India v1.c15.161

v1.c15.161

Thus have foreign races and foreign civilisations been brought into India, the history of which is in a large measure the story of the struggle between newcomers and the earlier inhabitants. Such invasions may be compared to waves breaking on the shore. Their force becomes less the farther they proceed, and their direction is determined by the obstacles with which they come in contact. The most effective of these obstacles, even when human effort is the direct means of resistance, are the geographical barriers which nature itself has set up. We shall therefore best understand the distribution of races in the sub-continent if we remember its chief natural divisions.