In the literary history of the Indian subcontinent, it appears that only the Tamil Sangam corpus has the pioneering assembly of secular Lady Bards. Those bards, from various walks of life, produced unparalleled secular works.
Lewis Henry Morgan (Lawyer/Amerindian Anthropologist 1851-1881), noticed a peculiarity between the Amerindians and Tamil Indians. Though separated by the vast swathe of land and ocean in between, yet having a commonality surprised him.
Tamil Bakthi literature is the collection of literary work composed around 6 AD by various poet-saints. It has information on the socio-cultural aspect of Tamil society. In some places, it has geological information relating to the pre-historic time of the ancient Tamil country.