In the seventh century, what is now called the United Kingdom was many kingdoms often at war. When one king, Oswald of Northumbria, became a Christian, he called for a missionary to bring the gospel to his region. A man named Corman was sent, but things didn’t go well. Finding the English “stubborn,” “barbarous,” and uninterested in his preaching, he frustratedly returned home.

“I am of the opinion,” a monk named Aidan told Corman, “that you were more severe to your unlearned hearers than you ought to have been.” Instead of giving the Northumbrians “the milk of more easy doctrine,” Corman…