Christianity/Catholicism and Pagan traditions basically absorbed each other, even within Christendom power struggles concessions were made to accommodate and consolidate power. Can see this today more obviously in South America where Catholicism and animist indigenous beliefs have blended together, Peloponneseia as well.
You mean putting up a Yule tree and trading presents like the Romans did, two traditions stolen by Christianity?
As others have said, pretty much co-opted from existing traditions https://historyofenglishpodcast.com/2013/05/05/episode-24-germanic-mythology/
Christianity/Catholicism and Pagan traditions basically absorbed each other, even within Christendom power struggles concessions were made to accommodate and consolidate power. Can see this today more obviously in South America where Catholicism and animist indigenous beliefs have blended together, Peloponneseia as well.