Hundred Years' War
Historians commonly divide the war into three phases separated by truces: the Edwardian War (1337–1360), the Caroline War (1369–1389), and the Lancastrian War (1415–1453). Local conflicts in neighbouring areas, which were contemporarily related to the war, including the War of the Breton Succession (1341–1365), the Castilian Civil War (1366–1369), the War of the Two Peters (1356–1369) in Aragon, and the 1383–85 crisis in Portugal, were availed by the parties to advance their agendas. Later historians adopted the term "Hundred Years' War" as a historiographical periodisation to encompass all of these events, thus constructing the longest military conflict in European history.
Hundred Years' War
Tensions between the French and English monarchies can be traced back to the 1066 Norman conquest of England, in which the English throne was seized by the Duke of Normandy, a vassal of the King of France. As a result, the crown of England was held by a succession of nobles who already owned lands in France, which put them among the most powerful subjects of the French King, as they could now draw upon the economic power of England to enforce their interests in the mainland. To the kings of France, this dangerously threatened their royal authority, and so they would constantly try to undermine English rule in France, while the English monarchs would struggle to protect and expand their lands. This clash of interests was the root cause of much of the conflict between the French and English monarchies throughout the medieval era.