Which English king led his army to victory at Agincourt?

The Battle of Agincourt was a major English victory in the Hundred Years' War. The battle took place on Friday, 25 October 1415 (Saint Crispin's Day) in the County of Saint-Pol, Artois, some 40 km south of Calais (now 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 V married the French king's daughter. Their son later became Henry VI of England and Henry II 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 psychotic illnesses with moderate mental incapacitation. Instead, the French were commanded by Constable Charles d'Albret and various prominent French noblemen of the Armagnac party.

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