J.R.R. Tolkien helped lead C.S. Lewis back to Christianity through conversations at Oxford.
Lewis and Tolkien became friends during the 1920s and belonged to the informal literary circle later known as the Inklings. Their discussions included mythology, language, literature, and Christianity. Tolkien, a Roman Catholic, challenged Lewis's view that Christian stories were merely one mythology among many.
Lewis described his conversion as a gradual process rather than a single isolated event. He became a theist in 1930 and returned to Christianity in 1931. Conversations with Tolkien and Hugo Dyson were especially important in the final stage of that change.
Tolkien and Lewis remained influential friends, although their relationship later became less close. Tolkien wrote The Hobbit and The Lord of the Rings, while Lewis wrote Narnia and major works of Christian apologetics.