C.S. Lewis became a Christian in 1931 after a conversation with J.R.R. Tolkien and Hugo Dyson.
Lewis had returned to belief in God before this event, describing himself as a theist by 1930. On the night of 19 September 1931, he talked with Tolkien and Dyson at Oxford about myth, sacrifice, and the relationship between pagan stories and Christianity. Lewis later described becoming a Christian believer in the period that followed.
The precise shape of his conversion is often simplified. Lewis had been raised in the Church of Ireland, abandoned Christianity during adolescence, and gradually moved back toward belief through reading, friendship, and philosophical reflection. His later writings frequently connected imagination, reason, and religious commitment.
Tolkien and Dyson were both members of the Inklings, the Oxford literary circle associated with Lewis. Their conversation influenced Lewis’s thinking, but it is not accurate to describe Tolkien alone as converting him in a single instant. Lewis’s religious development unfolded over several years.