The Christmas truce, also known as the Christmas Armistice, which took place at Ypres in Belgium (TV: Twice Upon a Time) on 25 December, Christmas Day, 1914, was a near-mythical event in World War I. (PROSE: This Town Will Never Let Us Go) For Christmas, British and German soldiers temporarily ceased fighting to sing Christmas carols, (TV: Twice Upon a Time) play football, share cigarettes, and pass around photographs of loved ones in No Man's Land. (COMIC: The Weeping Angels of Mons) The Ninth Doctor served as a referee for one of the football matches (COMIC: The Forgotten)
A couple of hours before the truce began, Captain Archibald Hamish Lethbridge-Stewart and other British soldiers were laying field telephone cables at the front line near Saint-Yvon. They were caught in another German bombardment and a subsequent attack. (PROSE: Twice Upon a Time) Lethbridge-Stewart was to die when he and a wounded German soldier encountered each other in a shell hole and shot each other after a long standoff. After encountering the Testimony who removed Lethbridge-Stewart from the battlefield to record his memories, the captain was accidentally displaced in time before the First Doctor and the Twelfth Doctor brought him back. However, the Twelfth Doctor adjusted the time period so that time resumed for the two men at the beginning of the Christmas truce, saving their lives.
The Twelfth Doctor explained to his earlier self that:
It never happened again, any war, anywhere. But for one day, one Christmas, a very long time ago, everyone just put down their weapons and started to sing. Everybody just stopped. Everyone... was just kind.The Twelfth Doctor's actions helped the First Doctor to understand the man he would become and eased his decision to regenerate. (TV: Twice Upon a Time)
The celebrations were also witnessed by the First Doctor, Steven Taylor, and Sara Kingdom; (PROSE: The Little Drummer Boy) the Fifth Doctor and Peri Brown; (PROSE: Never Seen Cairo) and the Ninth Doctor and Rose Tyler. (COMIC: The Forgotten)
The next day, soldiers resumed fighting. (PROSE: The Little Drummer Boy) Despite seeing the human face of their opponents, soldiers continued to find it necessary to fight in kill-or-be-killed situations. (COMIC: The Weeping Angels of Mons)
The truce was never repeated. On Christmas Day in 1915, some soldiers tried to organise another truce with their enemies but their superiors quelled the idea. Some men were even executed. (PROSE: Twice Upon a Time)
During World War II, Oskar Steinmann claimed the Germans observed a Christmas truce in 1939 and 1940 which the British refused to recognise, as part of a wider Nazi propaganda effort to paint the Allies as the war's aggressors. (PROSE: Just War)