By the 6th century bc at least 16 states had been established on the Indian subcontinent.
The Vedic people, who were nomads from the Eurasian steppes, migrated to the Indus valley beginning about 1500 bc. They introduced a caste system, which persists to the present day. The caste system divides all people into social classes with differing rights and obligations. It was a formal expression of the interdependent labor division seen in all civilizations. By the 6th century bc at least 16 states had been established on the Indian subcontinent.