The institution of caste is social rather than religious and has grown gradually: we know for instance that in the time of the Buddha it had not attained to anything like its present complexity and rigidity. Its origin is explicable if we imagine that the Indo-Aryans were an invading people with an unusual interest in religion. The Kshatriyas and Vaiśyas mark the distinction between the warriors or nobles and the plebs which is found in other Aryan communities, and the natives whom the Aryans conquered formed a separate class, recognized as inferior to all the conquerors. This might have happened in any country. The special feature of India is the numerical, social and intellectual strength of the priestly caste. It is true that in reading Sanskrit literature we must remember that most of it is the work of Brahmans and discount their proclivity to glorify the priesthood, but still it is clear that in India the sacerdotal families acquired a position without parallel elsewhere and influenced its whole social and political history. In most countries powerful priesthoods are closely connected with the Government under which they flourish and support the secular authority. As a result of this alliance, kings and the upper classes generally profess and protect orthodoxy, and revolutionary movements in religion generally come from below. But in ancient India though the priests were glad enough to side with the kings, the nobles during many centuries were not ready to give up thinking for themselves. The Hindu's capacity for veneration and the small inclination of the Brahmans to exercise direct government prevented revolts against sacerdotal tyranny from assuming the proportions we should expect, but whereas in many countries history records the attempts of priests to become kings, the position is here reversed. The national proclivity towards all that is religious, metaphysical, intellectual and speculative made all agree in regarding the man of knowledge who has the secret of intercourse with the other world as the highest type. The priests tended to become a hereditary guild possessed of a secret professional knowledge. The warrior caste disputed this monopoly and sought with less learning but not inferior vigour to obtain the same powers. They had some success during a considerable period, for Buddhism, Jainism and other sects all had their origin in the military aristocracy and had it remained purely Hindu, it would perhaps have continued the contest. But it was partly destroyed by Turanian invaders and partly amalgamated with them, so that in 500 A.D. whereas the Brahmans were in race and temperament very much what they were in 500 B.C. the Kshatriyas were different. It is interesting to see how this continuity of race brought triumph to the Brahmans in the theological sphere. At one time the Buddhists and even the Jains seemed to be competitors for the first place, but there are now hardly any