In which war did C.S. Lewis serve as a British Army officer?

C.S. Lewis served as a British Army officer in World War I.

Lewis volunteered for military service while studying at University College, Oxford. He was commissioned in the Somerset Light Infantry and served on the Western Front in France during 1917 and 1918.

He was wounded by shrapnel at the Battle of Arras in April 1918. After recovering, Lewis returned to active service, but the war ended before he could resume front-line duty. His wartime experiences later influenced his writing and his understanding of suffering, friendship, and mortality.

Lewis was not a soldier in World War II, although he became a prominent wartime broadcaster during that conflict. His broadcasts about Christianity were later collected in Mere Christianity, a work distinct from his military service and from his earlier experience as a junior officer.