C.S. Lewis converted to Christianity in 1931.
Lewis’s return to Christian belief developed over several years. He had abandoned Christianity during his youth and regarded himself as an atheist for a period. His conversations with J.R.R. Tolkien and Hugo Dyson, along with his own reading and reflection, helped him move first toward theism and then toward Christianity.
Lewis later described his conversion in Surprised by Joy. He wrote that he became a theist in 1929 and a Christian in 1931. The event is associated with a late-night journey to Whipsnade Zoo, when he traveled with Tolkien and his brother Warren. Lewis’s own descriptions emphasize a gradual intellectual and imaginative change rather than one simple dramatic moment.
The date is sometimes confused with 1929, because that was the year Lewis said he accepted the existence of God. The more specific date for his conversion to Christianity is 1931. He later became one of the twentieth century’s most influential Christian writers.