Yep, history would seem to cover this quite a lot.

I am kicking around the idea of doing some posts about Judaeo-Christian faiths from before the Council of Nicea. If you go back far enough the entire concept of Heaven/Hell, Satan/God goes away.

At one point there was only one place in the afterlife, and Satan was but a footnote mentioned as a helper.

They mingled with the Zoroastrians who had a dualistic system (not monotheism) and two places in after life.

Eventually we got Heaven, Hell, Satan, God, and you can thank that on Zoroastrians. Which has led me to wonder is it really a monotheistic religion now? They tend to have two. The good guy and the bad guy. It may have started with ONE, but this is true of many polytheistic faiths.