Hinduism in Tamil Nadu finds its earliest literary mention in the Sangam literature dated to the 5th century BCE. The total number of Tamil Hindus as per 2011 Indian census is 63,188,168 which forms 87.58% of the total popualation of Tamil Nadu. Hinduism is the largest religion in Tamil Nadu.
The religious history of Tamil Nadu is influenced by Hinduism quite notably during the medieval century. The twelve Azhwars (saint poets of Vaishnavite tradition) and sixty-three Nayanars (saint poets of Shaivite tradition) are regarded as exponents of the bhakti tradition of Hinduism in South India. Most of them came from the Tamil region and the last of them lived in the 9th century CE.
There are few worship forms and practices in Hinduism that are specific to Tamil Nadu. There are many Mathas (meaning monastic institutions) and temples based out of Tamil Nadu. In modern times, most of the temples are maintained and administered by the Hindu Religious and Endowment Board of the Government of Tamil Nadu.
The Cholas who were very active during the Sangam age were entirely absent during the first few centuries. The period started with the rivalry between the Pandyas and the Pallavas, which in turn caused the revival of the Cholas. The Cholas went on to becoming a great power. Their decline saw the brief resurgence of the Pandyas. This period was also that of the re-invigorated Hinduism during which temple building and religious literature were at their best.
The Cheras ruled in southern India from before the Sangam era (300 BCE – 250 CE) over the Coimbatore, Karur, Salem Districts in present-day Tamil Nadu and present day Kerala from the capital of Vanchi Muthur in the west, (thought to be modern Karur).
The Kalabhras, invaded and displaced the three Tamil kingdoms and ruled between the third and the seventh centuries CE of the Sangam period. This is referred to as the Dark Age in Tamil history and Hinduism in Tamil Nadu. They were expelled by the Pallavas and the Pandyas in the sixth century. During Kalabhras' rule Jainism flourished in the land of the Tamils and Hinduism was suppressed. Because the Kalabhras gave protection to Jains and perhaps Buddhists, too, some have concluded that they were anti-Hindu, although this latter view is disputed.