Vikings
The pagan Vikings were exposed to Christianity from the beginning of the Viking Age. They were surrounded by Christian countries. Early Christian missionaries were either enslaved or put to death. The Vikings came into contact with Christianity when they raided other areas around them. Viking raids produced many Christian slaves who were brought back to Scandinavia. They called Christians "Cross-men" because of the cross in their worship. In response many Vikings adopted Thors hammer as their religious symbol. When Vikings settled in Christian areas they converted to Christianity. There are still Headstones in England with both a cross and a hammer. Perhaps they thought it was better to be safe than sorry. That, or the more gods the better. As some Vikings turned from raiding to trading they found a nominal (in name only) profession of Christianity to be helpful. Scandinavia, their homeland, was slower to change to the Christian religion. But by the mid-11th century most of Norway and Denmark had converted. Sweden was converted by the mid-12th century. Overall Scandinavia and the peoples of the Baltic Sea were the last to accept Christianity.