Also, oral traditions in ancient cultures, some of which still exist in some countries have been found very reliable.

Give us an example?

Orpheus,
Have you ever heard of 'meme'. I believe this is the basic idea that you are referring to. Whatcha think?

meme : (pron. 'meem')
A contagious idea that replicates like a virus, passed on from mind to mind.
Memes function the same way genes and viruses do, propagating through communication networks and face-to-face contact between people.
the root of the word 'memetics', is a field of study which postulates that the meme is the basic unit of cultural evolution.

This is an interesting link regarding this.

http://www.christianitymeme.org/

David.