Jatis became the basis for organising society as many tribes and social groups were taken into caste-based society and given the status of jatis. Specialised artisans like smiths, carpenters and masons were also recognised as separate jatis by the Brahmanas.
With the support of Brahmanas, many tribes became a part of the caste system. But only the leading families could join the ruling class. A large majority joined the lower jatis of the caste society.
On the other hand, many tribes of Punjab, Sind and the North-West Frontier adopted Islam and refused to follow the caste system.