There are references in the Puranas, Hindu Texts,I would not call them figments of Imagination for most of them have been proved by Modern(?) Science to be true, about Stem Cell Birth,IVF.
The Sanatana Dharma was an intruder into Tamil Culture, it was imposed by the Brahmins who crossed over th India through the Khyber Pass, say the Rationalists and The self-styled scholars of Tamil. Yes , it was imposed to such an extent that the early Tamil literature Ahanaanuru records that the Chera King Udiyan Cheralaathan offered Tharpana to the people killed in the Mahabharata war.
The Bilva Leaves are used for the worship of Lord Shiva. Bilva leaves , like Tulsi can be used repeated for Pooja after washing them. Indonesia abounds in Bilva and Rudraksha Trees.which, again, is used for Shiva worship. The names of the Indonesian Rulers have Sanskrit base.
Here is yet another proof that the South was a part of Sanatana Dharma, Aryan Dravidian Theory is a myth and the people of North India and South India were a part of the Glorious Bharatavarsha. Rama's marriage was graced by the Kings of South India. Damayanti's Swayamwara had Tamil Kings presence. Lord Krishna married a Pandya Princess. Arjuna went on a pilgrimage to South and married a Pandya princess. Chola and Pandya Kings fought on the side of Pandavas in The Mahabharata War. Chera King fed both the Kaurava and Pandava armies and performed Sraddha , Obsequies for those killed in the war. The Vedas mention Lord Muruga as Skanda.
Vyasa in Sanskrit means exposition, Prose. The entire Bhagavatham is contained in this Sloka.