Which war did C.S. Lewis serve in as a second lieutenant?

C.S. Lewis served in World War I as a second lieutenant. He was commissioned in the Somerset Light Infantry and served on the Western Front in France during 1917.

Lewis volunteered for military service while studying at Oxford. He trained in England before being sent to France, where he experienced trench warfare and the dangers of the front line. His wartime service ended after he was wounded at the Battle of Arras in April 1918.

His close friend Paddy Moore was killed during the war, an event that affected Lewis deeply. Lewis later wrote about war, suffering, grief, and memory in ways that drew on both personal experience and broader Christian reflection.

A common mistake is placing his military service in World War II, when Lewis was already an Oxford academic and writer. During the Second World War, he became widely known for radio broadcasts about Christianity rather than for combat service. His World War I experience therefore belongs to the earliest adult phase of his life.