To create a duchy, kingdom, or empire:
- You must control 51% of the title's de jure counties (for duchies or kingdoms) or 80% (for empires)
- If a vassal, you cannot create a title higher than or equal to your liege's.
What is the point of creating a duchy ck2?
Allows your vassals to expand on their own (i.e. if your duke owns 2 of 3 counties in a duchy, you can press the claim on your own, or you can let him do it himself. Dukes are more likely to make improvements on their own (since they gain more money), so less micromanagement.
Should I create duchy ck2?
A duchie can be use to quell a lot of the problems if given at the right time. There is also a prestiege matter to consider. Creating the duchie gives you prestige and the more duchies you hold power over the more your monthy prestige will grow, even if they are held by your vassal.
