I was lazy. It was the first one out of about 600 that popped up when I googled "catholic church" and "pagan."
Anyhow, I thought that was just sort of a given. Those clever early Christian missionaries just overlaid their doctrine on top of the pagan worship that was prevalent at the time, so we got Christmas instead of the winter solstice, Easter in place of the spring equinox, etc.
I forget what Martin Luther's exact bitch was when he nailed those 95 theses to the local Catholic university's door. I think mostly he was upset that the pope back there in Rome got to be the utilmate authority on the latest insider news from God. The Catholic Encyclopedia hints that Luther may have been a psychopath, but they're probably a bit biased.
Talk about thread drift!