I would guess it was all european traditions that had a winter holiday. It's part of being seasonally attuned to the northern hemisphere, and probably necessary for survival. Yule may have been specifically a norse word, but other traditions had their equivalent. In any case, Christians and heathens are the same people. Just think of what heathen actually means -- of the heath, aka hill people. More or less equivalent to the "hillbilly" the modern day satanic denigrate us with.