C.S. Lewis became a Christian in 1931 after returning to religious belief.
Lewis had been raised in the Church of Ireland but became an atheist during his adolescence. Over time, conversations with friends and fellow writers—including Owen Barfield and J.R.R. Tolkien—helped him reconsider Christianity. Lewis described his return to belief in stages, first becoming a theist and later accepting Christianity.
He later wrote that his conversion to Christianity occurred in 1931. The process was intellectual as well as personal, and his subsequent books often addressed questions about belief, morality, suffering, and imagination. Lewis became associated with Anglican Christianity, although his writings reached readers across many Christian traditions.
A frequent oversimplification is to describe the change as a single instant. Lewis’s own accounts present it as a gradual movement from atheism to theism and then to Christian faith.