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What caused the conflict between Henry the Young King and Richard over Aquitaine?

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King Henry II and St. Thomas Becket — Henry II Henry II (left) disputing with Thomas Becket (center), miniature from a 14th-century manuscript; in the British Library (Cotton MS. Claudius D.ii).

The conflict between Henry the Young King and his brother Richard over Aquitaine was rooted in the internal instability of the Angevin Empire and the local resistance to Richard’s rule.

In 1183, the barons of Gascony—who were frustrated by Richard’s harsh governance as the duke of Aquitaine—revolted against him. Seeking to capitalize on this unrest and drive Richard from the duchy, the rebels enlisted the support of Henry the Young King and his brother Geoffrey of Brittany.1

This alliance led to a military campaign in which the Young King waged war against Richard in Poitou. The conflict ended abruptly when Henry the Young King died of dysentery in June 1183, causing the uprising to collapse. This struggle was part of a broader pattern of rebellion among the sons of Henry II, who frequently challenged their father’s authority and each other for control over his continental domains.213