At the age of 31, Milne married Daphne de Selincourt, a 23 year old pretty, affluent women. Shortly after their marriage World War I broke out and, despite opposing war, Milne enlisted in the army. He served in the Royal Warwickshire Regiment and was stationed in France. He was sent home for having very serious trench fever, which comes from lice (Hunter). However, he was then recruited by Military Intelligence to write articles in favor of the war (Finch). Sixteen years later he wrote about how war was intolerable in a piece called "War with Honour" (Thwaite).