How did the English possession of Guyenne contribute to the Hundred Years’ War?

The English possession of the duchy of Guyenne was a primary source of friction that fueled the Hundred Years’ War. As a vestige of the Angevin empire, Guyenne was held by the English king as a vassal of the French crown, creating a complex and often volatile political relationship.12

This arrangement contributed to the conflict in several ways:

• Legal Interference: French royal officials frequently exploited their suzerainty to intervene in the duchy’s internal affairs. They encouraged local malcontents to bypass the English administration and appeal directly to the Parlement of Paris, which severely strained diplomatic relations.1
• Homage Disputes: The requirement for English kings to perform homage to the French king for their continental lands was deeply resented and often performed grudgingly or delayed, leading to repeated crises.1
• Confiscation and War: Tensions over sovereignty and border incidents, such as the destruction of a French fortress at Saint-Sardos, prompted French kings to declare the duchy forfeit on multiple occasions. These declarations of forfeiture triggered military campaigns and periods of open hostility that characterized the Hundred Years’ War.12