Hundred Years' War (1415–53)
The Lancastrian War was the third and final phase of the Anglo-French Hundred Years' War. It lasted from 1415, when King Henry V of England invaded Normandy, to 1453, when the English lost Bordeaux. It followed a long period of peace from the end of the Caroline War in 1389. The phase was named after the House of Lancaster, the ruling house of the Kingdom of England, to which Henry V belonged.
Battle of Blanchetaque
Since the Norman Conquest of 1066, English monarchs had held titles and lands within France, the possession of which made them vassals of the kings of France. The status of the English king's French fiefs was a major source of conflict between the two monarchies throughout the Middle Ages. Over the centuries, English holdings in France had varied in size, but by 1337 only Gascony in south western France and Ponthieu in northern France were left. Following a series of disagreements between Philip VI of France () and Edward III of England, on 24 May 1337 Philip's Great Council in Paris agreed that the Duchy of Aquitaine, effectively Gascony, should be taken back into Philip's hands on the grounds that Edward was in breach of his obligations as a vassal. This marked the start of the Hundred Years' War, which was to last one hundred and sixteen years. In 1340, Edward formally assumed the title King of France.