Some people believe that Earth is only a few thousand years old, and that God created a kind of fake history by sprinkling dinosaur bones everywhere. Creators of lesser worlds, like the Dungeon Masters of their own D&D campaign, frequently do the same: Creating a fake history for a virtual world for their campaign to play in. Just recently Chris Perkins from WotC presented his historical campaign notes. But every time I read such campaign outlines, I ask myself "why bother?"

For me the main problem is how my players come into contact with all that history. I'm sure not going to start the campaign with a 4-hour history lesson, my players would be bored to death. A far more likely scenario is something like "Seeing the ruin, you succeed your history check and know that it is a remnant from the Nerathian Empire which fell over a century ago". For that I don't need a complete list of all the battles, emperors, and major events of the Nerathian Empire.

A secondary problem is that I don't plan my campaigns for 30 levels ahead. My current campaign is just over one year old, and the players are level 5. And I know what adventures I want to play for about the next year, up to level 10, but not beyond that. After all, D&D is interactive story-telling, and you never know how things evolve. So by making up my campaign as we go, I prefer to have a maximum of freedom. I create history when I need it for the adventure, instead of creating history at the start of the campaign and then running into conflicts between the history I told in advance and the history I need for a specific adventure.

Ultimately all this is a question of scale. My campaigns tend to work bottom-up, being created in mind with what the players see from their perspective. Given that this is medieval fantasy, it is only logical that this perspective is limited. Apart from some sages, people tend to know only local and recent history, and not be aware of the rise and fall of empires centuries ago. A top-down approach, where you spend hours creating a huge world and its history, most of which the players will never see, often leads to a waste of time. And risks forgetting the parts that the players actually care about. It is easy to create a fantastic world at a high level and end up lacking the detail that the players actually encounter.

So personally I don't even bother creating worlds. I take pre-made campaign worlds like the Forgotten Realms, and then fill them with my campaign. Sometimes I use the history of the Forgotten Realms if it fits, sometimes I modify stuff to fit my campaign. For example my campaign early on had the players encounter an avatar of Selune, an event which gave the campaign its name "The Favorites of Selune". So in consequence I turned the evil twin sister of Selune, Shar, into a major adversary for the campaign. Lore and created history has to serve the campaign, not the other way around.