Why do people think that Jon+Dany is incest?

[Greymoon]

Philip II of Spain and Anna of Austria, his niece. His sister was her mother

Joanna of Naples and Ferdinand II of Naples, her nephew

Pedro III of Portgual and Maria of Portugal, his niece

There are more. It happens. It just isn't as common as cousin marriages. They were rare but it did happen.

I admit I don't know much about history and am rather more interested in anthropology. Still I don't suppose it was a common practice. I know that Frederick I Barbarossa had his first marriage annulled on the grounds that he’d suddenly realized how closely he and his wife were "related". The argument – in this case the genealogical tree – was made up, but it shows that in the 12th century Germany, some people cared enough about incest that it could serve to legitimize a "divorce". It's rather agreed upon that Frederick I set his first wife aside because she wasn't a proper consort for the Holy Roman Emperor and that he needed a good and valid reason to plead his case with the Pope; hence the made up "blood relation"...or something.

[CosimaistheHottest]

I admit I don't know much about history and am rather more interested in anthropology. Still I don't suppose it was a common practice. I know that Frederick I Barbarossa had his first marriage annulled on the grounds that he’d suddenly realized how closely he and his wife were "related". The argument – in this case the genealogical tree – was made up, but it shows that in the 12th century Germany, some people cared enough about incest that it could serve to legitimize a "divorce". It's rather agreed upon that Frederick I set his first wife aside because she wasn't a proper consort for the Holy Roman Emperor and that he needed a good and valid reason to plead his case with the Pope; hence the made up "blood relation"...or something.

Yea. If you notice in history, they married cousins all the time and they got papal dispensation for it. Then when they wanted to get an annulment. They would argue on the grounds of consanguinity.

[Alhazred]

Rhaenyra (if I got the name right), the mother of Aegon III married her uncle.

There is no question that the Targs practice what is (even by Westerosi standards) considered "incest".

[jarl the climber]

That sounds like Norfolk, in England.

West Virginia in the states.