A study of the Sanatana Dharma and Tamil throws some interesting questions.
The Vedic Dharma seems, it has been held, to have originated in the North of Vindhyas, Sarasvati valley.
Recent studies, excavations of archeological sites relating to Hinduism, Sanatana Dharma around the world, from Australia to South America,Europe, Africa, Russia,China and information on the practices of the aborigines in various parts of the world,indicates that the Sanatana Dharma was prevalent in one form or another in all these places,
Western scholars used this to invent the Aryan Invasion Theory, that is a Group called Aryans, invaded India thought the Khyber Pass in the Northern part of India and had influenced the thought processes of the people living in India.
This Theory, deliberately floated by the British mainly, to subjugate India , now stands discredited.
Please read my detailed Post on The Aryan Invasion Theory, Myth.
The Aryan theory could not explain the references to the Sanatana Dharma in Tamil Literature, South India.
Tamil language dates back to thousands of years and the Vedas quote them and they, in turn quote Tamil.
The oldest Tamil site has been found in Pallavaram, Chennai .(dated around a Million years.)
‘Archaeologists have discovered India’s oldest stone-age tools, up to 1.5 million years old, at a prehistoric site near Chennai. The discovery may change existing ideas about the earliest arrival of human ancestors from Africa ‘.
Lord Krishna participated in the Tail Sangam as an Invitee.
Please refer my Post on this.
He married a Pandyan Princess and had a daughter through her, and got his daughter arrived to a Pandyan Prince , gave her a dowry of one hundred Yadava families to provide her and her children with Milk and Curds.
The Chera King Perunchotru Udiyan Neduncheralaathan participated in the Mahabharata War as the provider of food to both the Kaurava and Pandava armies.
He had Tharpana performed for those who died in the War.
Now comes the curious part.
Lord Rama ‘s ancestor Satyavrata Manu migrated fro the Dravida Desa(South of Vindhya Mountains) with his sons and his son Ikshvaku founded the Ikshvaku founded the dynasty, named after him, Lord Rama Belongs to this dynasty.
Shiva and His son Ganesha left, during the Great Flood, the time when Satyavrata Manu migrated to North, through the Middle east, traveling through europe, Africa,South America, North America((US), Central America, finally landing in the Arctic, where the Rig Veda was composed.
Please refer my Post on this.
Then they returned to India, then called the Bharata varsha and this entry was used to be denoted as the entry of the Aryans.
The Artifacts, archeological finds, cultural similarities, Languages of the found around the world indicates this.
Please read my posts on this.
Now Six avatars of Vishnu are from the South.
Matsya is from the Ocean and as such we can not ascribe a location on the earth.
Kurma is in the Ocean again, but there is a Temple where Kurma avatar took place.
Vamana Avatar was in Kerala and the place where Bali had his kingdom was on the banks of Narmada, where the capital of Bali was situuated.
The place Varaha killed Hiranyakasipu is in Nepal, V(B0araha Kshetra), yet there is legend that Varaha is from Tirupati which is Adivaraha Kshetra.
Narasimha is from Ahobilam ,Andhra Pradesh.
Parashurama Avatar is from the South, Kerala.
Kalki is expected to manifest in the South.
Later Avatars from Lord Rama are from the North of Vindhyas.
Now Shiva is not mentioned in the Vedas excepting in the Sri Rudram,
‘Nama sivaaya cha, Siva dharayacha’
No special Sukthas directly addressed to Shiva are found.
Shiva means Auspiciousnees , as he etymology goes.
There is not much reference in the North of Vindhyas of Shiva as much as Vishnu or Rama, Krishna.
Shiva is considered to be Chief deity among the Tamils, though the early Tamil Literature has Gods assigned for each landmass as Murugan, Krishna, Kotravai(Durga)Varuna and Indra.
But Shiva is taken as the First Siddha, followed by Agastya and others.
The Thirumandiram of Thirumoolar contains the Yoga thoughts, Advatita and Tantric practices that are unique.
And this is much earlier to Ramayana and Agastya is referred to have founded Tamil , being handed over by Lord Shiva.
Ravana entered into a treaty with a Pandya King.
Many of the Tamil practices were incorporated by Apasthamba in the Vedic rituals, like the Mangalya Sutra.
Though there are common factors between the Sanatana Dharma and the Tamils, yet there is a uniqueness in Tamil practices, which are, curiously enough, not against the Vedic practices but reinforces them.
Many of the Avatars of Shiva have not been reported in the Literature of the North of the Vindhyas, though Puranas, mention Shiva avatars in the South,
Shiva is described as Piravaa Yaakaip Periyon,The Eldest, though Unborn.
He is considered as the First Guru, Adi Shiva, the First Siddha, the First Yogi.
The sixty-four avatars of Shiva in Madurai are not mentioned in the North.
The Agamas which came later to Vedas specified rules for the construction of Temples, though Temple worship is not mentioned in the Vedas.
Tamil Kings followed this and one finds ancient temples, both for Vishnu and Shiva in the South in the Agama style.
These temples, though the Agamas started with out the authority of the Vedas gained currency and helped Hinduism.
Considering all these facts, I tend to think the worship of Shiva in the South preceded the Sanatana Dharma of the North.
And one may note that the Rig Veda was composed in the Arctic.
Sanatan Dharma in the south, Dravida seems to have preced the Sanatan Dharma fro the North of the Vindhyas.