Dreams

How did our forebears handle dreams? For sure they couldn't know what a dream is, so they took certain dreams for real messages from their gods. Even I have sometimes dreams which I cannot tell from fiction or truth, they are so real, some of them even carry a message (without intention by "someone" who might be behind the dream).
I suggest that a lot of ancient stories and religious stories came to life by narrations of people who took their dreams for reality.