Medieval Geopolitics: Gascony and the Causes of the Hundred Years’ War

By Andrew Latham and Rand Lee Brown II

“Sir, does it not seem to you that the silken thread encompassing France is broken?” ~ Sir Geoffrey le Scrope, Lord Chief Justice of England, 1324-1338

In my very first Medieval Geopolitics column I described the two forms of political war –“constitutive war” and “configurative war” – that, along with religious war (the crusades), defined the range of types of large-scale organized violence in the later Middle Ages.  In the following few columns, I’m going to be joined by Captain Rand L. Brown II, USMC in exploring the way in which political or public war manifested itself in what has come to be known as the Hundred Years War (1337-1453).  We start by looking at the “configurative war” fought between the kingdoms of England and France during that conflict. After that, another collaborator and I will look at the “constitutive war” fought between England and Scotland during that same protracted conflict.


While the titanic clash of medieval superpowers that took place over 117 years later known collectively as the Hundred Years War would rage from Scotland to Spain and everywhere in between, one place that seems to forever lie at the heart of the conflict are the warm, sunny, and wine-sodden vistas of Bordeaux and Gascony.  Much ink has been spilled from the 14th Century when the war began to the present day on the various geopolitical, legal, and sociological factors that led to this truly remarkable conflict to become what it did and how it would reshape the entire social, cultural, and political destinies of not just its combatants, England and France, but of all Western Europe.  However, the fact that the ancient English Plantagenet claims to Gascony and the perennial attempts of the French Crown to annex these lucrative lands served as the principal causus belli I will argue to be beyond question.

Before we analyze the impact of Gascony on the Hundred Years War itself, we must look back at the story of how the kings of England came to even hold a claim to it in the first place.  To start, one must always remember that the Plantagenet line of English kings ultimately descended from the Franco-Norman adventurer, William the Conqueror, and his usurpation of the English Crown from its Saxon owners at Hastings in 1066.  The Anglo-Norman regime William introduced was thoroughly French in language, culture, and politics and the cross-cultural ties with medieval France ran deep among the new English nobility. These ties were only strengthened when, in 1151, King Henry II “Plantagenet” of England (himself a native of Anjou, France) married the captivating Aliénor d’Aquitaine, Duchess of Aquitaine and owner of virtually the entire southwestern quarter of modern France, adding these lands to his already impressive empire and giving the Kings of England greater territorial ownership of France than her own Kings.

France in 1328, with Gascony part of the English crown. Map by Goran tek-en / Wikimedia Commons

However, Not long after Henry’s reign, much of these lands would be chipped away at and lost to ambitious and capable French kings like Philip II “Augustus,” who eventually succeeded in retaking the ancestral Plantagenet lands of Normandy and Anjou from Henry’s feckless youngest son, John I.  But somehow, throughout this chaotic period the English managed to keep hold of Gascony and its prize city, the bustling wine-trading port of Bordeaux – no doubt with the aid of the native Gascon nobility who prized their quasi-independent status under England far above subservience to the more authoritarian regime rising in Paris. In an agreement that all but assured the continuation of conflict over this region, King St. Louis IX issued the Treaty of Paris in 1259 with King Henry III, formally making the English Kings feudal vassals of the Kings of France in return for their ownership of Gascony. This created an incredibly awkward and friction-prone status quo in which the heads of an independent state were politically and legally subordinate to the heads of an entirely separate and (at that time) far more powerful state for the sake of their overseas territories – a status quo whose ultimate consequences would result in creating the very conflict it was designed to prevent.

Exacerbating this arrangement was the critically important economic status Gascony possessed within the medieval European markets and especially for England. By 1327, the city of Bordeaux and her population of around 30,000 rivaled (and possibly exceeded) the population of London.  Nestled on the Gironde Estuary where the Garonne River empties into the Bay of Biscay, the ports of Bordeaux served as the primary maritime trade hub for all the mercantile traffic coming and going between Northern Europe and the Iberian Peninsula. Of critical importance to England, the lands surrounding Bordeaux had produced some of the finest quality wines in Europe since before the days of the Roman Empire and still do even today. The trade of this precious resource earned more revenue for the English Crown in 1327 than all revenues in England, Wales, and Ireland combined and formed the third critical corner of the “Trade Triangle” of 14th Century England along with English wool and Flemish textiles. This economic value was not missed by the Kings of France who, while certainly coveting such wealth for themselves, would remain content to use the threat of confiscation as a geopolitical cudgel over their English rivals whenever they felt so inclined.

This uneasy status quo would be completely turned on its head with the arrival of King Edward III on the scene.  Viewing himself as the last legitimate male heir to the Capetian Dynasty of France through his mother, Isabella (daughter of Philip IV), Edward III rejected the status quo that English kings since his great-grandfather had lived under and brought about a paradigm shift in Anglo-French relations by not only completely rejecting the suzerainty of the cadet Valois kings of France over him, but also challenging their very legitimacy of their claim to the throne of France itself.

The catalyst that spurred Edward to make such a bold political maneuver was when Philip VI declared Gascony to be forfeit in 1337 in retaliation for Edward’s continued attacks on Scotland and his refusal to extradite Robert of Artois (a high profile fugitive from France who sought refuge in England). Claiming sovereignty over Gascony ultimately proved to be a political, economic, and reputational “bridge too far” for 14th Century England.  In the short-to-medium term, however, the English enjoyed considerable success, largely due to the fact that from the outset the French simply failed to grasp just how far Edward III would go to press his claim to sovereignty over Gascony. This failure to understand English resolve to hold Gascony would cost the French dearly in the decades to come.  Indeed, it would take nearly two generations of bloody defeats before they finally grasped the realities of this new war with “L’ancien Ennemi” and turned the geopolitical tables on the English.  In the interim, though, the war would completely transform the kingdoms of both England and France.


Further Reading:

Green, David.  The Hundred Years War: A People’s History.  New Haven CT: Yale University Press, 2014.

Seward, Desmond.  The Hundred Years War: The English in France 1337-1453.  New York: Penguin Group, 1978.

Dr. Andrew Latham is a professor of political science at Macalester College in Saint Paul, Minnesota. He is the author, most recently, of a monograph entitled Medieval Sovereignty, to be published in 2020 by ARC Humanities Press.  You can visit Andrew’s website at or follow Andrew on Twitter @aalatham


Capt Rand Lee Brown II is a commissioned officer in the United States Marine Corps currently assigned to Marine Forces Reserve.  Holding a Master of Arts degree in Military History from Norwich University with a focus on medieval warfare, Capt Brown has written on military history for a variety of forums, including the Marine Corps Gazette and

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Top Image: Bibliothèque nationale de France MS Français 2663 fol. 271r