The popularity of the oral epic of Valmiki%u201As Ramayan was gradually converted to a religious text by Brahmin authors. Slowly the ideal man, Ram, began to be see as an incarnation of Vishnu. Moreover, in this version, Sita's chastity is once again called into question upon her return to Ayodhya and this time she is banished forever to Valmiki's hermitage where she gives birth to twin sons, Lav and Kush.
The multiple versions of Ramayan include a Buddhist version (dating to anywhere between the 4th and 2nd centuries BC) in which Sita is the sister of Ram. When Ram was crowned king on his return to Ayodhya after his exile, Sita was made queen consort and they ruled jointly for 16,000 years, and became the originators of the royal clan. There is also a Jain version (the Paumacharyam) at the end of which the main protagonists become Jain ascetics. According to this version, far from being a villian, Ravan is a devoted Jain.
