still united by the bond of common religious and social institutions in the face of the indigenous populations whom they drove before them, or reduced into subjection and slowly assimilated as they moved down towards and into the Gangetic plain. As the conditions of life grew more complex, with increasing prosperity and probably longer intervals of peace, differentiation between classes and professions grew more marked. There was time and leisure for thinking as well as for fighting, for contemplation as well as for action. The "bright" gods that Nature had conceived for the early Aryans were fashioned and refashioned by speculations already laden with the gloom of melancholy and awesomeness that pervades India. Caste, it may be inferred from the Sanskrit word _Varna_, which means colour, originally discriminated only between the Aryan conquerors of relatively fair complexion and the darker aborigines they had subdued. It was extended to connote the various stratifications into which Hindu society was settling, and in the stringent rules which governed the constitution of each caste, and the relations between the different castes, the old exclusiveness of tribal customs was perpetuated and intensified. To the supremacy which the Brahman, as the expounder of the scriptures and of the laws deduced from them, and the ordained dispenser of divine favour, through prayer and sacrifice, was able to arrogate to his own caste, the code of Manu, above all others, bears emphatic witness: The very birth of Brahmans is a constant incarnation of Dharma.... When a Brahman springs to light he is born above the world, the chief of all creatures, assigned to guard the treasury of duties, religious and civil. Whatever exists in the world is all in effect, though not in form, the wealth of the Brahman, since the Brahman is entitled to it all by his primogeniture and eminence of birth.