Battle of Waterloo

The Battle of Waterloo took place in 1815 in the Belgian province of Waterloo. It saw the defeat of the reconstituted French imperial army of Napoleon Bonaparte by the British under the Duke of Wellington and the Prussians under Marshal Blucher. Although the time-manipulating Players attempted to intervene by assassinating the Duke before the battle, and subsequently issuing false orders to the English forces' Prussian reinforcements, these attempts were thwarted by the Second Doctor and his companion Serena; Serena sacrificed herself to take the shot that would have killed the Duke, and the Doctor subsequently posed as Napoleon to safely pass through French territory and deliver the message to the Prussians. This defeat marked the final end of the French empire, Bonaparte being deposed as Emperor for the second time, and once again set into exile. (PDA: World Game)

After the battle, Wellington told the Doctor, "The only thing sadder than a battle lost, is a battle won." Some time later, the Fourth Doctor considered how right he was. (EDA: The Eight Doctors)

Wellington fought alongside Oliver Blazington at the battle. (NSA: The Eye of the Jungle)

'Waterloo' has become a byword for defeats; for example, the Fourth Doctor referred to the defeat of the Sontarans as "their Waterloo". (DW: The Sontaran Experiment)

While teaching at Farringham School for Boys, John Smith gave a lesson on Napoleon's defeat at Waterloo. (DW: Human Nature)

In a history project for school, Clyde Langer and Luke Smith were required to show the battle strategies by Wellington and Napoleon at the battle. The pair re-enacted the battle on Mr Smith. (SJA: The Last Sontaran)

Alternate Outcome
In an alternate timeline where the Players assassinated the Duke of Wellington prior to the Battle, the French forces won, with the Countess convincing Napoleon to continue his plans for the expansion of France regardless of the strain that he was putting on his men. As a result, the empire he created had collapsed by 1865, with the countries he had conquered reverting back to smaller kingdoms that engaged in more minor conflicts with each other for additional territory. This timeline was undone when the Second Doctor learned how the Duke had died and travelled back to the night of his assassination to avert it. (PDA: World Game)