Agincourt, Battle of, October 25, 1415, an English victory over France in the Hundred Years' War. It was fought near the village of Agincourt, 33 miles (53 km) west of Arras in northern France. Henry V of England, reasserting his claim to the French throne held by Charles VI, invaded France and took Harfleur. By marching toward Calais, Henry provoked an attack by the much larger French army under the Constable Charles d'Albret. The French depended on armored knights, and at this period plate armor had become very heavy. Bogged down in mud, the knights were slaughtered by English archers.