Tamil religion is the earliest documented devotional tradition in South Asia in a language other than Sanskrit. The Sangam poems already distinguish landscapes with their own deities, and the god of the hills, Murugan, is the one most strongly identified as Tamil, worshipped at the six houses, the arupadai veedu, and honoured at Thaipusam with vows, carried burdens and the piercing of the body.
The bhakti movement that reshaped Hinduism began here. From roughly the sixth century the Nayanmar, sixty three saints devoted to Shiva, and the Alvars, twelve devoted to Vishnu, composed hymns in Tamil that were sung in temples and later collected as canonical scripture, so that a vernacular corpus stands beside the Sanskrit one and is used liturgically. Indira Peterson's translations of the Shaiva hymns and Norman Cutler's study of their poetics show what the movement did. It made the direct relation between a devotee and a god, expressed in the devotee's own language, the centre of religion.
The temple is the other Tamil institution. The great complexes at Chidambaram, Madurai, Srirangam and Thanjavur are towns organised around a sanctuary, with festival processions moving the deity through streets laid out for the purpose.