you may have heard of the concept of a "cargo cult", which came from a primitive tribe that first encountered modern people in the form of an fighter pilot.

primitive minds, and the mangling of stories via chinese whispers style corruption could easily explain that what we call gods were actually just people with high tech shit.

like when the aztecs saw cortez for the first time, they thought the gods had returned.

to them, the gods had white skin, and devices that made big loud flashes that kill things. probably they had clean clothes too. and they probably understood that their puny weapons were worthless anyhow. this wasn't the battle hardened zulus, this was a culture that hadn't seen white people probably in at least hundreds of years (the movement of people between south america and europe/africa is likely to have happened a lot more than our history books recognise, because there is a whole chain of islands and a thick ridge that you can sail between them with pretty low tech stuff).

plenty of cool time travel stories that make some interesting points about this too, there is a series of stories in the Doctor Who episodes that relate to this sort of phenomenon.