The Battle of Agincourt was a major English victory in the Hundred Years' War. The battle occurred on Friday, 25 October 1415 (Saint Crispin's Day), near modern-day Azincourt, in northern France. Henry V's victory at Agincourt, against a numerically superior French army, crippled France and started a new period in the war during which Henry married the French king's daughter and then Henry's son, Henry VI, was made heir to the throne of France.

Henry V led his troops into battle and participated in hand-to-hand fighting. The French king of the time, Charles VI, did not command the French army himself as he suffered from severe, repeating illnesses and moderate mental incapacitation. Instead, the French were commanded by Constable Charles d'Albret and various prominent French noblemen of the Armagnac party.

The battle is notable for the use of the English longbow, which Henry used in very large numbers, with English and Welsh archers forming most of his army. The battle is also the centrepiece of the play Henry V, by William Shakespeare.