A Timeline for Indian Epics

Some people have asked whether we could go back to the drawing board at this point in the discussion and draw up a timeline of various events. This is an incredibly difficult task, as no effort in this regard will be undisputed

Here are a couple of nice articles on this topic:

http://web.cocc.edu/cagatucci/classes/hum210/tml/indiatml/indiatml1.htm
http://en.wikipedia.org/wiki/History_of_India

Since we can't really pinpoint the dates of when the epics occurred, I think we should start with the following assumptions

1. First there were vedas - Rig Veda, Sama Veda, Yajur Veda, Atharva Veda composed around 1500 BC
2. Then came Upanishads - starting around 800BC
3. Then it was the turn of Puranas like talking about creation (Brahma), sustenance (Vishnu) and extinction (Shiva)
4. The Epics came last around 300 BC and in the case of Ramayana, maybe even after Christ (AD). However there is no conclusive evidence that Vyasa and Valmiki lived during this time. It is possible that they created some scriptures several centuries earlier which were transcribed later. I don't know much about this