J.R.R. Tolkien served in the Battle of the Somme in 1916.
After completing his studies at Oxford, Tolkien was commissioned as a second lieutenant in the Lancashire Fusiliers. He served on the Western Front during the Somme offensive, one of the largest and bloodiest campaigns of the First World War.
Tolkien took part in the Battle of the Somme and was later returned to England after contracting trench fever. His wartime experience profoundly affected his generation, and biographers have discussed possible echoes of trench warfare in his depictions of desolation, friendship, endurance, and loss.
It is important not to treat Middle-earth as a direct allegory of the First World War. Tolkien rejected simple one-to-one allegorical readings. Still, the war was a major part of his life and historical context, and 1916 is the key year connected with his Somme service.