gotra is a Brahminical system which came into vogue(circulation) after about 1000 BC. This Brahmanical method was to Classify People(Especially Brahmanas) in terms of gotra. Each gotra was named after a Vedic Seer(sage). The members of the same gotra were considered to be the descendants of the sage. Important rules of gotra. After marriage, women had to leave their father's gotra and follow their husband's gotra. Men and women belonging to the same gotra could not marry each other.