DID CATHOLIC EUROPE adopt restrictions on cousin marriage from the Romans? (I have taken liberties with capitalization in the quoted text. For the original formatting, click the link.)
There is a direct link between ancient Rome’s and medieval/modern northern Europe’s cousin marriage avoidance. That link is quite obviously the Catholic Church which adopted all sorts of Roman institutional structures and practices; but more specifically I’m referring to several of the Church Fathers, the earliest of whom lived in the Roman Empire itself and who, no doubt, were very aware of the Roman avoidance of cousin marriage and very likely, having been raised “in Rome,” had even internalized the idea as a natural and good one.
Here, in sequence, are the guys that I think passed the Romans’ notion of avoiding close marriage down to us (by introducing the idea into canon law).
Earlier: Attempting to Explain the Rise of Western Europe: hbd* chick’s Big Summary Post on the Hajnal Line.