
Well tho back in the day. Royals and many people in earlier Times married cousins,brothers and sisters and or kept it in the family. I guess that's why they have so many insane people lol never know. Besides All the hazard's. But many people didn't care about that. The only thing that changes was stupid laws. But in woke countries you can still marry your cousins or your mother's brother
Etc. Not sure about other things love Aunt or uncle or whatever lol. But I do know for a fact you can marry cousin's.

Royal families throughout history were known for inbreeding They wanted their lines to be pure royal so, What better way than to literally have it remains within the family, right?, for example, if everyone in a royal family has blue eyes and the king married a non royal, with brown eyes, it disturbs the bloodline, because the next generation children might have brown eyes and NOT blue, so to keep up the appearance, many royal families converted to incest, which caused birth defects etc.
incest doesn't bother me unless you make children together, im fine with adopting, but no having children on ur own, thats a risk nobody wants to take.