How about Northern Ireland? Are you a filthy partitionist or are you filthy United Ireland scum? Or are you going to skip the middle man and go revisionist history and just preemptively prevent the Troubles by allowing us to genocide the Emerald Isle and make it properly English?
The
partition of Ireland didn't happen until
1920. It's not relevant to a medieval game, and given divergent history in a game spanning 800 years that has player agency, it should basically never happen.
EDIT: if you look at the history, the deal was that Northern Ireland was the part that had the most english protestant immigrants, they basically made the location of Belfast into a fully-fledged city. So if Addemup wanted this modeled in the game it'd have to track nationality %'s of populations. Then you could get periodic uprisings, maybe triggered by such things as taxation, and they are less likely in provinces with more of your own countryfolk / religion.
This would lead the player to want to create a foothold of your own loyalists. If you sent a few immigrants to every Irish province, they'd merely be absorbed by the Irish within a couple of generations (have a chance for immigrants to marry other immigrants or locals, then have a % chance for the babies to consider themselves locals or immigrants).
This would actually be a really interesting modelling problem. e.g. you'd want to say send enough immigrants to Belfast such that it's 60% English, but then you don't want that just rocketing to 100% without any further involvement. What could be modeled is a value for a population's resistance to intermarrying. e.g. intermarriages happen fast at first, but each time they do, the remaining population gets slightly more resistant to the idea (e.g. they represent more of the people who aren't ok with intermarrying). so there's mixing but not at a steady rate.