>>60491030Sheltered upbringing predisposes them to people that live within their narrow bubble
Mores against 'marrying down' limit their pool of potential partners
Political circumstances can limit access to foreign partners that are less likely to be related to them
And centuries of breeding within a narrow circle greatly increases the likelihood that any two members of that circle are blood related.
Entire kingdoms changed their fundamental course of history because centuries of weird breeding left nobles in line to inherit foreign thrones. Britain became a saxon kingdom because of blood ties, then french province in the middle ages, then a dutch province in the 17th century. A polish crusader state formed the German Empire because a noble was distantly related to the elector of Brandenburg. And for a while, the monarchs of france, spain and half of central europe were all the same family.
There's a good reason we did away with that shit. It was making things weird.
