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.
Mary of Waltham
Seven years previously, King Philip VI of France attempted to confiscate the Duchy of Guyenne (also referred to as Aquitaine) from Edward III – an event that traditionally marks the beginning of the Hundred Years' War – after which Edward used military force, diplomacy and marital links to strengthen his claim to the French throne. In the Duchy of Brittany succession dispute, he supported John of Montfort since a close alliance to the English crown with Brittany would give Edward access to the port of Brest for use by English troops. When Montfort was captured, his wife, Joanna of Flanders, took over the campaign and, during the siege of Rennes, received military support from Edward. In return, she promised her son John (later John IV, Duke of Brittany) to one of his daughters.