100 years ago, according to Wikipedia, in January 1917 J. R. R. Tolkien, on medical leave from the British Army during #WW1, begins writing The Book of Lost Tales (the first version of The Silmarillion), starting with the "Fall of Gondolin"; thus Tolkien's mythopoeic Middle-earth legendarium is first chronicled in prose.
He delayed enlistment until completing his degree and, upon completing his Finals, was then commissioned as a temporary second lieutenant in the Lancashire Fusiliers on 15 July 1915. He trained with the 13th (Reserve) Battalion on Cannock Chase, Staffordshire, for eleven months, and on 2 June 1916, Tolkien received a telegram summoning him to Folkestone for transportation to France.
On 5 June 1916, Tolkien boarded a troop transport for an overnight voyage to Calais. Like other soldiers arriving for the first time, Lieutenant Tolkien was sent to the British Expeditionary Force's (BEF) base depot at Étaples. Lieutenant Tolkien left Étaples on 27 June 1916 and joined his new unit at Rubempré, near Amiens. Tolkien found himself commanding enlisted men who were drawn mainly from the mining, milling, and weaving towns of Lancashire.
Tolkien arrived at the Somme in early July 1916. In between terms behind the lines at Bouzincourt, he participated in the assaults on the Schwaben Redoubt and the Leipzig Salient. On 27 October 1916, as his battalion attacked Regina Trench, Tolkien came down with trench fever, a disease carried by lice, common in the dugouts and was invalided to England on 8 November 1916.
Tolkien's battalion was almost completely wiped out following his return to England. Being deemed medically unfit for general service, he spent the remainder of the war alternating between hospitals and garrison duties. It was at this time that his wife Edith bore their first child, John Francis Reuel Tolkien. In a 1941 letter, Tolkien described his son John as "(conceived and carried during the starvation-year of 1917 and the great U-Boat campaign) round about the Battle of Cambrai, when then end of the war seemed as far off as it does now".
In his preface to the second edition of The Lord Of The Rings, denying his book's relevance to WW2, Tolkien wrote: "One has indeed personally to come under the shadow of war to feel fully its oppression; but as the years go by it seems now often forgotten that to be caught in youth by 1914 was no less hideous an experience than to be involved in 1939 and the following years. By 1918 all but one of my close friends were dead."
The sacrifices made by the many who served in The Great War, and lost so much, shall not be forgotten.