Chivalry and Betrayal: The Hundred Years' War
In 1435 Bedford died and sworn enemies Charles VII and Phillip, Duke of Burgundy joined forces to get the English out and with Henry VI reluctance to wage war and to maintain peace by marrying Margaret of Anjou. Charles had no intention of peace and used cannon and sieges to retake France and Normandy culminating in the defeat of the English at the Battle of Castillon in the last English territory of Gascony ending the hundred years war.
List of wars by death toll
""'Note: the identity of a single "war" cannot be reliably given in some cases, and some "wars" can be taken to last over more than a human lifetime, e.g.
"Reconquista" (711–1492, 781 years)
"Muslim conquests in India" (12th to 16th c., 500 years)
"Crusades" (ten or more campaigns during the period 1095–1291, 196 years),
"Mongol conquests" (1206–1368, 162 years),
"early Muslim conquests" (622–750, 128 years),
"Hundred Years' War" (1337–1453, 115 years).