C.S. Lewis became a Christian in 1931, after a long period in which he identified as an atheist. His return to Christianity developed through conversations with friends and fellow writers, including J.R.R. Tolkien and Hugo Dyson.
Lewis had grown up in the Church of Ireland but rejected Christianity during adolescence. As an adult, he gradually moved from atheism toward belief in God. He later described this change in autobiographical works including Surprised by Joy, though his spiritual development was complex rather than a single sudden event.
The 1931 date is especially associated with Lewis’s acceptance of Christianity. He first became a theist and then embraced Christianity more fully. His discussions with Tolkien, a Roman Catholic, helped him think about the relationship between myth, imagination, and Christian belief.
His conversion strongly influenced the later direction of his career. He became one of the twentieth century’s most prominent Christian writers, producing works such as Mere Christianity, The Problem of Pain, and The Screwtape Letters. Lewis’s earlier atheism is therefore an important part of the story he told about his own intellectual development.