Talk:Cleopatra/@comment-39255282-20190620191250/@comment-36277500-20190702123114

Not only Ptolemies - every Egyptian dynasty was endogamic. Ptolemies didn't invent this, it was an archaic custom from about 2000 years BCE - it was as ancient to Cleopatra as she is ancient to us!

Egyptian heirdom rules were not based on "father to son", but "father to daughter". So if a prince wanted to be a crown prince, he had to marry a crown princess... who was his sister. Mostly half-sister, because since Egyptians practiced polygamy (pharaoh used to have a harem), there were many half-siblings.

People 2000 years BCE might not know about genetics, but they knew about economy - they intended to save the wealth in the royal family, that's why they ordered endogamy in it.

I even dare to say that Ptolemies were healthier than older dynasties - Egyptian genetic pool was mixed with relatively fresh, Grecian blood (after Alexander III the Great's conquest).

However, Ptolemies didn't dare to break free from endogamy - it would be impossible to openly oppose the tradition that survived thousands years. Even Cleopatra VII was forced to marry respectively her two brothers (and they both "accidentally" died). Romancing Caesar and Antony was the best thing she could do, from the point of view of genetics.