Historically, the roots of Buddhism lie in the religious thought of ancient India during the second half of the first millennium BCE. That was a period of social and religious turmoil, as there was significant discontent with the sacrifices and rituals of Vedic Brahmanism.[note 15] It was challenged by numerous new ascetic religious and philosophical groups and teachings that broke with the Brahmanic tradition and rejected the authority of the Vedas and the Brahmans.[note 16] These groups, whose members were known as shramanas, were a continuation of a non-Vedic strand of Indian thought distinct from Indo-Aryan Brahmanism.[note 17] Scholars have reasons to believe that ideas such as samsara, karma (in the sense of the influence of morality on rebirth), and moksha originated in the shramanas, and were later adopted by Brahmin orthodoxy.[note 18][note 19][note 20][note 21][note 22][note 23]