Tamil and Sanatana Dharma walked hand in hand together, contrary to the misinformation that the Tamils were inimical to Sanatana Dharma .
I have recorded facts from History that how Tamils were a part of Sanatana Dharma, with additional contributions from them,Tamil Kings took part in the Marriages/Wars in the North of Vindhya Mountains.
Tamils celebrated the Lifting of Govardhan Giri by Lord Krishna by alluding to it through the Indra Vizha, The Festival for Indra.
This has been documented in earlier Tamil Sangam Works and in detail in the Silappadikaaram.
The Vedic Gods, Subrahmanya, Devi, Varuna,Vishnu and Indra were worshiped, assigning each of them to a unique terrain.
‘Vaadai Vizha or Vadavazhi Vizha, the festival of welcoming the Lord Surya back to home, as He turns northward, celebrated on December 21/22 (Winter Solstice) (the sixth day of Panmizh[Maargazhi]). It is sung about in Akanauruanthology.
The Surya Siddhanta defines Uttarāyaṇa (उत्तरायण, উত্তরায়ণ, ઉત્તરાયણ), or Uttarayan as the period between the Makara Sankranti(which currently occurs around January 14) and Karka Sankranti (which currently occurs around July 16). The term Uttarayana is derived from two different Sanskrit words “uttara” (North) and “ayana” (movement) thus indicating a semantic of the northward movement of the Sun on the celestial sphere. This movement begins to occur a day after the winter solstice in December which occurs around 22 December and continues for a six-month period through to the summer solstice around June 21 (dates vary ). This difference is because the solstices are continually precessing at a rate of 50 arcseconds / year due to the precession of the equinoxes, i.e. this difference is the difference between the sidereal and tropical zodiacs. The Surya Siddhanta bridges this difference by juxtaposing the four solstitial and equinotial points with four of the twelve boundaries of the rashis.
Citation and Reference.