Hundred Years' War: The army of Henry V of England, consisting mostly of archers, unexpectedly defeated the numerically superior French cavalry at the Battle of Agincourt (pictured) on Saint Crispin's Day.

The Hundred Years' War was a series of conflicts between the kingdoms of England and France and a civil war in France during the late Middle Ages. It emerged from feudal disputes over the Duchy of Aquitaine and was triggered by a claim to the French throne made by Edward III of England. The war grew into a broader military, economic, and political struggle involving different factions from across Western Europe, fueled by emerging nationalism on both sides. The periodization of the war typically charts it as taking place over 116 years. However, it was an intermittent conflict which was frequently interrupted by external factors, such as the Black Death, and several years of truces.