What was the name of the battalion in which J.R.R. Tolkien served during the First World War?

J.R.R. Tolkien served in the 11th Battalion, Lancashire Fusiliers during the First World War.

He was commissioned as a temporary second lieutenant in 1915 after studying at Oxford and receiving military training. In 1916 he went to France and took part in the Battle of the Somme. The experience brought him into the industrial-scale violence of trench warfare.

Tolkien later became ill with trench fever and was sent back to England. Most of the close friends he had known as a student, including members of the group called the Tea Club and Barrovian Society, were killed in the war. That loss profoundly affected him.

Readers sometimes assume that one fictional battle corresponds exactly to the Somme. Tolkien rejected a simple one-to-one interpretation, but wartime experiences contributed to the emotional atmosphere of his writing, including themes of friendship, sacrifice, ruined landscapes, and the cost of conflict.