Thats two hundred years and would cover the end of Plantagenet reign and the Tudor era.
Henry VIII reign happened during that period, at the beginning of your time period everyone would be catholic and at the end Queen Mary of Scotts was executed because the idea of a Catholic on the throne was unthinkable.
The UK is littered with castles and estates, normally they focus on specific historic events which happened at that location.
If you signup to social media it will pester you for your email contacts, location and hobbies/interests.
Building a signup wizard to use that information to select a instance would seemto be the best approach.
The contacts would let you know what instance most of your friends are located (e.g. look up email addresses).
Topic specific instance, can provide a hobby/interests selection section.
Lastly the location would let you choose a country specific general instance.
It would help push decentralisation but instead of providing choice your asking questions the user is used to being asked.