Origins and Causes of the Hundred Years’ War
The Hundred Years’ War had no single cause, and that is precisely the point. By the time Philip VI confiscated the duchy of Aquitaine on 24 May 1337, the two kingdoms of England and France had been sliding towards open war for the better part of a century, and the immediate disputes that triggered the conflict were the visible surface of a much deeper inheritance. This section unpacks that inheritance in three articles: what caused the Hundred Years’ War, the legal and political history of the English claim to the French throne, and the early campaigns of Edward III in France between 1337 and 1360. The reader who comes to this section looking for a single trigger will leave looking for a single resolution — the causes are tangled, and the scholarship on them is more tangled still.
Deep Roots: Feudal Inheritance and the Loss of Normandy
The conflict begins with a fact that looks, from a modern vantage, almost absurd: from 1066 until 1204, the king of England was also a substantial landholder on the French mainland, and the largest single magnate in the kingdom of France. Henry II’s marriage to Eleanor of Aquitaine in 1152 brought the Plantagenet dynasty an empire that ran from the Scottish border to the Pyrenees, an inheritance greater than the French king’s. Philip II Augustus set about dismantling it the moment Henry II’s sons gave him the chance. The confiscation of Normandy in 1204, followed by the loss of Anjou, Maine, Touraine, and Poitou over the next twenty years, reduced the English king to his remaining possession of Aquitaine and a handful of northern outposts. The English crown never accepted the loss. Edward I, Edward II, and Edward III each in turn tried to recover the inheritance by diplomacy, by proxy war, and, after 1337, by direct invasion.
A second root lies in the feudal relationship that survived the loss of Normandy. The English kings, as dukes of Aquitaine, were vassals of the French king for their remaining continental territories, and the ceremony of liege homage was a constant source of friction. The legal obligation to perform homage for Aquitaine gave the French crown a lever over the English king that no English treaty could fully neutralise; it was the pretext for the summons that Edward III defied in 1337, and it was, in the longer run, one of the things the war was fought to abolish. The Treaty of Brétigny of 1360, which gave Edward III full sovereignty over an enlarged Aquitaine in exchange for his renunciation of the French throne, was meant to settle the question; it did not. The detailed analysis of the feudal and territorial background is in what caused the Hundred Years’ War, and the legal history of the claim is in the English claim to the French throne.
The Crisis of 1328 and the Outbreak of War
The political crisis of 1328 gave the inheritance dispute a king to attach itself to. The last direct Capetian king, Charles IV, died on 1 February 1328 leaving only a daughter and a pregnant wife; the wife produced a daughter, and the French throne passed, by the application of the so-called Salic Law, to the nearest male heir through the male line, Philip of Valois, crowned Philip VI on 29 May 1328. Edward III of England, whose mother Isabella was Charles IV’s sister, was the nearest male relative by blood, and his claim was, on the strict principles of primogeniture, the stronger one. The Salic Law, an obscure Frankish custom, was mobilised to exclude him. The compromise that held the peace for nine years — Edward performing homage for Aquitaine in 1329–1330, and accepting the Valois title — collapsed in the 1330s under the weight of three separate disputes: the French crown’s tightening judicial control over Aquitaine, the English crown’s support for the Flemish cloth cities in their revolt against the count of Flanders, and the Breton War of Succession, which broke out in 1341 over the duchy that commanded the Channel coast. The confiscation of Aquitaine in May 1337 was the trigger; the English response, beginning with the campaign of 1339 and culminating in the great naval victory at Sluys on 24 June 1340, was the war.
Jonathan Sumption, in the first volume of his narrative, treats the outbreak as the product of structural pressures that made war more rational than peace for both sides; John Favier, in his more sceptical French account, emphasises the accidents and the personalities, particularly the role of Robert of Artois, the dispossessed nephew of Philip VI whose intrigues gave the English court a permanent French interlocutor. The military dimension of the opening campaigns, from Sluys to the Treaty of Brétigny, is treated in the early campaigns of Edward III in France, and the same period is followed into its battles in Key battles and military leaders.
Articles in this section
- What caused the Hundred Years’ War?
- The English claim to the French throne
- Edward III’s early campaigns in France