I'm a Hindu by religion. And I really respect my religion like I respect others. But from my childhood, I'm listening a lot of stories about Hindu Gods and Goddess which are interrelated to each other. But I'm thinking who wrote these stories, and any man/woman who first knew these stories, how did he/she get to know, because he/she was not God. So I want to know how and from where these stories came to mankind from God.
Many mythological stories we hear today have an oral tradition, that is, they were never explicitly written down anytime, but passed from generations through word of mouth.
To get some idea of "when", the Vedic age is approximately believed to be from 500 BC-150 BC and it is possible that the characters of Gods and the stories may have taken shape around that period.