"Never before has such terror appeared in Britain as we have now suffered from a pagan race," wrote English scholar Alcuin. He was referring to the A.D. 793 raids on the monastery at Lindesfarne, off the eastern coast of Scotland. The pagans were "Northmen" (or Norsemen) and this raid inaugurated what is called "the age of the Vikings."

"Behold the church of Saint Cuthbert," wrote Alcuin, "splattered with the blood of the priests of God, despoiled in all its ornaments; a place more venerable that all in Britain is given as a prey to pagan peoples."

The Vikings, swift and merciless marauders, were pagans who attacked Christian settlements from Ireland to the Mediterranean for the next 200 years. They brought with them not only blood and destruction, but also a violent paganism, in which the gods Thor, Wodin, and Frey, an unholy trinity of power and magic, threatened to undue the 500-year work of Christian missionaries. No wonder that from the Lindesfarne raid on, monks regularly prayed, "From the fury of the Northmen, O Lord deliver us."

Not only did the Lord deliver England from the pagan Vikings, over the next 400 years he also converted the marauders. It is one of the most remarkable and little-known stories in Christian history—the conversion of the Vikings. It happened slowly and piecemeal—a combination of missionary effort, key royal conversions, and mostly day-to-day witnessing by common people who bumped into Christians as they traded goods. But by 1200, the Scandinavian countries became thoroughly Christian, and after the Reformation, thoroughly Lutheran.

God is about the business of changing not just people, but whole cultures. It doesn't happen overnight and not as neatly as we'd like. But it happens—if we continue to pray and have patience—even from one generation to the next.