1914

World War I began in 1914. (TV: The War Games)

In this year, Josie Laws McRae was born in Scotland. (PROSE: The Wheel of Ice)

Freddie was born in Russia. (PROSE: The Clockwise Man)

Edith Harcourt began teaching at Brideport Elementary School. (COMIC: The Piggybackers)

Before the war
In April, Bernice Summerfield watched over John Smith, the Seventh Doctor in human form, in the town of Farringham. The Aubertides attacked, searching for him. (PROSE: Human Nature)

In June, French archaeologists discovered a Krivani interstellar drive. With the help of a German spy, the Seventh Doctor and Ace retrieved it from British agents. (PROSE: Ante Bellum)

Beginning of World War I
On 28 June, the assassination of Archduke Franz Ferdinand of Austria-Hungary (COMIC: The Dalek Project) by Gavrilo Princip in Sarajevo, Bosnia triggered a series of events that rapidly escalated into Earth's first global conflict: World War I. (PROSE: Human Nature) Unknown to the general populace, however, the start of the war was influenced by the passage of the Nemesis statue around Earth in November 1913. (TV: Silver Nemesis)

In August, the United Kingdom entered the war. On 21 August, British troops were preparing to defend the town of Mons in Belgium from the advancing German troops. The Battle of Mons was the first battle of the British Army in the war. There were rumours of Weeping Angels making German soldiers vanish during the battle. (COMIC: The Weeping Angels of Mons)

In October, Germany bombarded Antwerp. Using her yacht, a British woman named Jessica Borthwick evacuated numerous Belgians across the English Channel while under German fire. (AUDIO: Brotherhood of the Daleks)

On 25 December, the Ninth Doctor and Rose Tyler visited a World War I battlefield and participated in a football match between the British and German soldiers during the Christmas truce. (COMIC: The Forgotten) Elsewhere on the Western Front, the Fifth Doctor witnessed another such football match while temporarily separated from Peri Brown. (PROSE: Never Seen Cairo) The First Doctor, Steven Taylor and Sara Kingdom likewise visited the Western Front at this time. (PROSE: The Little Drummer Boy) The First Doctor and Twelfth Doctor also visited the Christmas truce, saving Archibald Hamish Lethbridge-Stewart and a German soldier's lives. They watched the subsequent Christmas truce football match, then each departed to regenerate. However before doing so the Twelfth Doctor met glass avatars of Bill Potts, Clara Oswald, and Nardole. He also observed how empty the battlefield was, remarking the war represented him as the lone survivor. (TV: Twice Upon a Time)

The Third Doctor, Tobias Philby and Thomas visited a World War I battlefield. (COMIC: The Amateur)

The Tenth Doctor visited the battlefields of the First World War in Belgium twice, once with Rose Tyler and once with Daniel Francis Thompson. (COMIC: Warfreekz!, PROSE: Deep and Dreamless Sleep)

Francis Wilberforce was killed in Flanders. (AUDIO: The Wrong Doctors)

Behind the scenes
According to a sighting report sent to Whoisdoctorwho.co.uk by someone under the username "Matneee", the Ninth Doctor was present at Ferdinand's assassination. He shouted at the archduke, telling him to duck.