What two groups in ancient India challenged Brahmanism and why?

Two significant groups that challenged Brahmanism in ancient India were the Buddhists and the Jains. Both movements arose as reactions to the rigid Caste System and the ritualistic practices prevalent in Brahmanism. They emphasized personal spiritual experience, ethical conduct, and liberation from the cycle of rebirth (samsara) through one's own efforts rather than reliance on priestly rituals. Additionally, both groups promoted ideas of equality and rejected the hierarchical structures upheld by Brahmanical traditions.