The Sanatana Dharma walked hands in hand with Tamils.
As early as 96 AD reference had been made by an anonymous author about Kanyakumari.
Periplus of Erythrean Sea” (81-96 AD) refers to Kanyakumari.
Eratosthenes 4 who visited India in about 276 B.C.
In Poromcode, near Kaliyakkavilai, a neolithic celt was discovered which may roughly be dated to 1500 to 1000 B.C. (period of neolithic civilisation in Tamil Nadu).
A hand made coarse earthern jar and other relics were found near Thoothur village in Kanniyakumari district. The shape, fabric and the decorations indicate that they are probably of the megalithic or early historic period.
From the legends and traditions existing in these regions, it has to be believed, beyond doubt, that a great city flourished in these regions during the megalithic or early historic period and that it might have been similar to the one which existed in Mohanjadaro and Harappa. Since, the relics of this period remained in the sea bed, it has to be believed that this civilisation was wiped out due to sea erosion.
‘The Kingdom of the Ayis flourished to the South of the Chera Kingdom and it extended from Nelcynda’ 140 AD (obviously identical to Nelcynda of the Periplus) to ‘Komari’.-Ptolemy.
: The earliest known rulers of this region belonged to the Ayi dynasty, whose remote ancestors are referred to as the ‘Hida Raja’ in the Asokan Rock Edicts II and XIV. The term ‘Hida’ is the variation of ‘Ida’ or ‘Idaya’ a synonym of ‘Ayar’ which takes its singlular form as ‘AYI’. Probably the region around ‘Pothiyil’ mountains was ruled by them. Thus the antiquity of the ‘Ayis’ dates back to 250 B.C. and possibly still earlier. The mention of them in the Asokan Edicts along with the Cholas, Pandyas, Cheras and Sathiyaputras as independent rulers outside the Mauryan dominion, enhanced their importance.
Ayi Andiran : He was one of the many Vei Chieftains who ruled over several parts of the Tamil country. Legends are many about the ancestry of the Vel Cheiftains. To mention one, they are said to have issued from a ’Homakundam’.Domain of Ayi Andiran was the area around the Pothiyil Hill which is the Southern most section of the Western Ghats…
Maduraikanchi, a literary work lends support to the view that Kanniyakumari was in possession of the Pandyas. ‘Purananuru’ mentions the Pandya ruler as the lord of the Pahruli river which had its confluence with the sea at Kanniyakumari. Besides early inscriptions also mention Nanjilnadu as part of the Pandya Empire. Vadimbalambaninra Pandyan, it is said, by his engineering skill harnessed the course of this river. The Goddess Kanniyakumari was regarded as the family deity of the Pandyas..
This clearly shows the interaction between the Tamils and Sanatana Dharma since 3 Century in Kanniyakumari.
Let me add that Kanyakumari district has two famous temples, Suchindram Sthanumalayar Temple and Kanyakumari Temple at Kanyakumari.
Suchindarm has a rare temple where Brahma , Vishnu ans Shiva are found in one idol.
Kanyakumari was a part of Tamil Nadu when Tamils’s land extended beyond Kanyakumari and the land was was consumed bya Tsunami.