 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 the end of the war seemed as far off as it does now".Tolkien was promoted to the temporary rank of lieutenant on 6 January 1918.When he was stationed at Kingston upon Hull, he and Edith went walking in the woods at nearby Roos, and Edith began to dance for him in a clearing among the flowering hemlock.