How common was close-family incest in history?

Probably a noble/monarchical thing. You know, keeping it in the family.

>>2491729
Something like Child Harold (fiction character made by Byron)

>>2491635
Cousin marriage was so common in almost all societies as to be literally unremarkable. It's really only in the last 50 years maybe where it's become taboo. In the West, at least. Surely someone has the map that shows in the Middle East and Indian subcontinent it's still common today.

Cousin marriage is not even really that bad genetically, especially if it's just once off. If you do it for a long time in a small community, then freaky genetic disease most certainly will become more common. That's bad. The benefit is that you keep wealth/property in the family.

I have a friend whose parents are cousins. This is in Germany, they married in the early 80s. They grew up in different smallish towns not too far from each other, but both families were also good friends, and it just kinda happened. No one cared. He has one grandmother who also the product of cousin marriage.

>>2491635
The Hawaiians and a lot of polynesian islanders practiced incest as well, in face the first wife of King Kamehameha was the product of direct sibling incest and thus considered akin to a goddess I think

>>2491635
Cousin marriage really isn't that close though. It's common in a lot of societies, even nowadays. Sibling and parental incest is what's taboo almost everywhere.