C.S. Lewis became a Christian in 1931 after describing a conversion during his Oxford years.
Lewis had been raised in the Church of Ireland but became an atheist in adolescence. During the 1920s, conversations with Christian friends, including J.R.R. Tolkien and Hugo Dyson, contributed to a gradual change in his thinking. Lewis later described his movement back toward belief as a reluctant or resistant process rather than a single sudden event.
In 1931, he became a Christian. He later distinguished between becoming a theist and accepting Christianity, describing those stages as occurring through his Oxford years. His conversion shaped much of his later writing, including The Problem of Pain, Mere Christianity, and The Chronicles of Narnia.
Lewis’s friend Tolkien was a Roman Catholic, while Lewis became an Anglican. This difference is sometimes blurred in popular accounts of their friendship. Their shared interest in myth and Christian ideas helped influence their conversations, but Lewis’s conversion was his own intellectual and spiritual journey.