As society grew more complex, new skills were needed and jatis (caste groups) formed based on occupations like smiths, carpenters and masons. Powerful new Rajput clans also emerged between the 11th-12th centuries and replaced older rulers in agricultural areas. Gradually, with Brahmin support, many tribes joined the caste system though most became part of the lower jatis, while elite tribal families could join the ruling class, demonstrating how state formation was linked to tribal social changes.