Hindu mythologies are literary works and not historial data.

The story writers of this mythology may have been influenced by historic events.

For instance Ramayana. There may have been a truthfull prince called Rama who defeated Ravana. Ramanaya is a story written by Valmiki based on this incident. Naturally like our movies exageration of events is all too natural (Remember special effects in Ramananda Sagars TV version of Ramayana.)