The Cato Institute reports:
Now we have another big, monocausal explanation for Western Europe’s rise that is utterly different from the rest, although it has faint echoes of Max Weber. The WEIRDest People in the World, by cultural psychologist Joseph Henrich, gives the credit for European prosperity to the Catholic Church. Why? Because the Church completely obliterated traditional kinship ties through increasingly rigid restrictions on whom one could marry.
There's more:
The process started in 597 AD when a monk, Augustine of Canterbury, was trying to convert the Anglo‐Saxons of England. He wrote to Pope Gregory I (now St. Gregory the Great), asking if some prevalent marriage customs would be allowed once the natives became Christian. The pope’s reply was strict. He rejected marriage to close relatives or to close in‐laws (in‐laws are called “affines” by anthropologists). He banned the adoption of children. He prohibited concubines. (Divorce was already prohibited, based on Jesus’s words in Scripture.)
It had a big outcome:
By 1063, the Synod of Rome (the assembly of bishops for Italy) prohibited marriages between all cousins up to sixth cousins. Certainly, that was extreme. Who is your sixth cousin? Someone who has the same great‐great‐great‐great‐great‐grandparent. It is unlikely that you would know who such a relative is. And if you found a seventh cousin to marry, you had to be sure that he or she was not also an affine or a godparent. (The sixth‐cousin “incest” rule was later relaxed to prohibit just third and closer cousins from marrying one another. While the rule was in force, the convenient “discovery” that one was married to a distant cousin could be reason for an annulment.)
You might say the Muslim countries evolved in a different way.
