“ Somewhere along the line, someone very powerful lost their marbles. Literally. Possessing a marble allows incredible clarity of thought about a particular related subject.”
“ Village has a nearby natural substance that comes from the ground and burns well when lit. They use it only locally and try not to let the secret get out.”
“ The religion believes in reincarnation, but that you will be reborn in the past. People of today are those re-born of tomorrow, with some discarded as trash. The most pure will be eventually reborn in the mythical paradise-like past, where people lived for hundreds, or maybe even thousands of years.
This goes nicely with beliefs into foresight (you know a little about the future because you have been there), but also to many complaints of how things are going always from bad to worse.”