Just a theory

[Mister Agenda]

I’ve always thought  that religion was first invented to explain what our early ancestors didn’t understand.

Where would the idea of a god or gods come from, what would cause people to actually try and conceive of such, there is no evidence to support your thought. We do see these things in religion after they were established, on this I agree. But the concept of a higher being, they had no references to go to that end.
GC

You're really stumped by where ideas come from? Do you think the idea of aliens came from aliens and if they weren't real we'd never have thought of them? Ideas come from our dreams and our imaginations.

When we sleep, we seem to go places and encounter people and things, while everyone can confirm that you never left your spot by the campfire. It sure seems like there's an invisible part of you that can walk around and have adventures while you're asleep. While you're dreaming you can encounter people who are dead, talking animals (talking anything, really), and gods (and these days, aliens).

Not to mention our ancestors were as capable of making up stories as we are. Storytelling is what humans do when its dark and there's a fire going. Memorable stories are more likely to remembered and passed on, and throwing in some superhuman feats by the heroes and villains makes the story more memorable.