The Caste System
Brahmanical teaching divided all men into four principle castes : The Brahmans who prayed; the Kshatriyas who fought; the Vaisyas who worked; the Sudras who performed unclean tasks, and - outside the castes - the Pariahs, or 'Untouchables' who were barely tolerated.
The apparent injustice of such a rigid caste system was made tolerable by the belief that souls were born to happiness or sorrow according to their conduct in their previous life. This kept alive the hope for social improvement in the next cycle of rebirths.
The caste system - inhuman as it was - brought an unexpected advantage to India. More castes could be added in later times and those castes made it easy for India to bring in new groups of people. No radical adjustments of previous habits was required of the newcomers, who simply became one more among the many castes of the land.
The fragile character of most Indian states, on the other hand, resulted from the fact that no ruler could command the undivided loyalty of peoples who felt themself to belong to a caste rather than a state.