What was J.R.R. Tolkien’s wartime experience that influenced the Dead Marshes in The Lord of the Rings?

J.R.R. Tolkien’s wartime experience at the Battle of the Somme influenced the Dead Marshes in The Lord of the Rings. Tolkien served in the British Army during the First World War and was sent to France in 1916 as a second lieutenant in the Lancashire Fusiliers.

He took part in the Somme offensive and developed trench fever later that year. Many of his fellow officers and friends were killed, an experience that shaped his understanding of loss, endurance, and the destructive character of industrial war.

The Dead Marshes are not a direct historical retelling of the Somme, and Tolkien did not reduce Middle-earth to a simple allegory of the First World War. However, scholars and readers often note parallels between the marshes, blasted landscapes, and memories of fallen soldiers seen beneath the water.