In episode 3, I posit that your world history should be virtually unknown, and discovery should be a natural part of the game, both for the GM and the players. I (seemingly) made the case that you shouldn't invest in your world history because it's mostly a waste of time.
This is part of a series, which starts right here. I'm a decent GM. I'm been running this kind of game since 2010. I have a comfortable pattern that leads to games that are generally fun, and don't require a lot of prep.