The significance of the Battle of Agincourt, fought on October 25, 1415, during the Hundred Years' War, lies in its demonstration of English military prowess despite overwhelming odds. The English army, led by King Henry V, faced a much larger French force but achieved a decisive victory thanks to superior tactics, including the effective use of longbowmen. This battle boosted English morale, solidified Henry V's reputation, and changed the course of the war. The outcome intensified the conflict, leading to further English claims in France and influencing the nature of warfare in the medieval period over subsequent decades.