The Hundred Years War was a long conflict which, at various stages, involved the Kingdom of England and the Kingdom of France. It began, for hereditary reasons, in 1337 and was fought on French territory. It marked a decisive turning point in field military and siege tactics. During the Hundred Years War the cavalry was the flagship of the French armies. However, since the early stages of the war, where heavy French defeats were recorded in the battles of Crecy and Poitiers, until the battle of Azincourt in 1415, British troops prevailed in all military operations. Only since 1429, with the undertaking of Joan of Arc during the siege of Orleans, did the French troops find moral and determination.