Which First World War battle inspired J.R.R. Tolkien’s Dead Marshes, according to biographical accounts?

The Battle of the Somme is commonly associated with the wartime experience that influenced J.R.R. Tolkien’s Dead Marshes.

Tolkien served as a second lieutenant with the Lancashire Fusiliers during the First World War and fought in the Battle of the Somme in 1916. The battle’s devastated landscape, mud, danger, and mass casualties have often been discussed alongside the imagery of the Dead Marshes in The Lord of the Rings.

The connection should be described as an influence rather than a literal one-to-one source. Tolkien drew on many experiences, memories, languages, and literary traditions when creating Middle-earth. He also lost several close school friends during the war, an experience that shaped his understanding of friendship and sacrifice.

The Somme offensive began on 1 July 1916 and continued until November. Tolkien became ill with trench fever and was sent back to England, ending his active service at the front.