C.S. Lewis converted to Christianity in 1931 after a period of intellectual and spiritual change that included discussions with J.R.R. Tolkien. Lewis had returned to belief in God in 1929, but his acceptance of Christianity came in 1931.
Lewis described his conversion as developing through conversations with friends and fellow scholars. Tolkien, an English literature professor and Roman Catholic, was among the people who helped Lewis reconsider the relationship between myth, imagination, and Christian belief. Another important influence was Hugo Dyson, an English scholar and fellow member of the Inklings.
The date is sometimes simplified or misreported because Lewis’s movement from atheism to Christianity was gradual rather than a single event. His return to theism preceded his conversion to Christianity by about two years.
After 1931, Christianity became central to Lewis’s fiction, literary criticism, and apologetics. Works such as The Problem of Pain, Mere Christianity, and The Chronicles of Narnia reflect that later intellectual and religious outlook.