Ancient India

Talking about Ancient India, I had always wondered how life in India was before the series of Invasions started out here. Were the natives more gullible and vulnerable then now? From whatever I have read about people of Ancient India, they had knowledge and wisdom in abundance. Vedas stands a proof to it.

Was sanskrit the language they largely spoke? Where has Sanskrit disappeared from the Modern India? Whatever history we know about India today is after the inception of Invasions, what happened to the history before that?

We may never be able to reach to the depth of Indian History as probably all the genuine references has been destroyed. And its difficult to accept any theory without some strong evidence.

http://www.samskrita-bharati.org/books/prideofindia.pdf