The Arab invasion was a failure. It attacked from the wrong quarter, occupied the least productive province, and was too feebly supported to spread farther. We hear no more of the Arabs as conquerors in India. The role devolved upon the Turks, and when we speak of the Mohammedan empire in India we mean the rule of the Turks. Their invasion was no part of the expansion of Islam as a religious movement.
It was merely the overflow of the teeming cradle-land of Central Asia, the eastern counterpart of those vast migrations of Huns, Turks, and Mongols, which from time to time swept over Europe like a locust cloud. Huns and Scythians had poured into India in prehistoric ages through those grim north-western passes
which every now and then opened like sluice-gates to let the turbid flood of barbarians down into the deep calm waters of the Indian world. Their descendants still muster in tribes and clans on the borders of Hindustan, and bring strange customs and beliefs to mingle
with that old religion of the Vedas which the Aryan forefathers of the Brahmans and Rajputs bore with them through the same narrow entry.
Following in their track, Alexander the Great led his armies to meet Porus on the Hydaspes; and after him came Greco-Bactrian legions to inspire new ideas of art and civilization, and to learn perhaps more than they taught. Finally the Moslem Turks discovered the same road, and when once they had become familiar with the way, they came again and again on successive inroads, until
