As of today, not many are aware of history of Buddhism in Tamil Nadu: some details

By  Shiva Shankar 
Reference Counterview post "Madras HC verdict on Thalaivetti Muniyappan opens up space for Buddhist history", here is some information about Buddhism in Tamil Nadu:
1. Buddhism in Tamil Nadu
In our travels in search of the ancient Buddha statues of Tamil Nadu, we came across many Buddha and Bodhisattva statues from the 1st – 16th Century CE timeframe. As of today, though Tamilians are not so much aware of the history of Buddhism in the Tamil land, and though many of them consider Buddhism to be a foreign system belonging to Sri Lanka, the fact is the other way around. From almost every district of Tamil Nadu, ancient Buddha statues have been discovered. Tamil Nadu had wide-spread presence of all forms of Buddhism including Theravada, Mahayana and Vajrayana. Many great Buddhist scholars and Yogis were also from there including Bodhidharma, Dignaga, Buddhaghosha, Dhammapala, Dharmakirthi, Chandrakirthi and Dharmapala. According to Tibetan master Taranatha, Guru Padmasambhava stayed in Tamil Nadu for many years and taught Mahayana and Vajrayana Buddhism there. There are also historical accounts of Theravada Buddhism in Sri Lanka being revived in the 13th Century by inviting monks from Tamil Nadu.

2. Imagining a Place for Buddhism: Literary Culture and Religious Community in Tamil-Speaking South India, Anne E. Monius
Non-Hindu communities such as Buddhists, Jains and Ājiīvakas played such an important role in South Indian literary and religious culture, and in the administration of the state between the fourth and seventh centuries that the later Śaiva traditions labeled this period the Kalabhra interregnum—the interruption of the wicked ones. Despite their presence in Tamil inscriptional, archaeological and literary record, their significance has been undermined in historical narratives that have valorised the triumph of Tamil Śaivism, casting Buddhists and Jains as ‘foreigners’ to be spurned, ridiculed and dismissed as anti-Tamil. In this pioneering study, focusing on two extant Buddhist Tamil texts—Maṇimēkalai (a sixth-century poetic narrative) and Vīracōliyam (an eleventh-century treatise on grammar and poetics)–Anne Monius, Professor of South Asian Religions at Harvard Divinity School, sheds light on the role of literature and literary culture in the formation, articulation and evolution of Tamil Buddhist religious identity and community.
The cover features S. Anvar’s photograph of a 12th century statue of the Buddha at the Paravai bus stop, Perambalur, Tamil Nadu.