Sorry, I should have specified, before Christianity. :facepalm:
The point was more along the lines of they weren't generally European. Druids would have been restricted to the Celtic lands of France, western Germany, Austria, Switzerland, Spain, and the British Isles. You wouldn't have found German or Viking or Slavic or Roman or Saami druids, though they may have had individuals with a similar function. Point is, while the Nords have a moderate Celtic influence, shaman would better suit them, I think. The Nords don't seem to have the sort of organized religion that a priest-class suggests.