Thomas, Earl of Lancaster—the son of Edmund Crouchback and Blanche of Artois— having led the baronial opposition to his cousin Edward II, had become England’s effective ruler by the time of Edward's decisive defeat at Bannockburn.

Edward recovers power, however, with the help of a new favorite, his chamberlain Hugh le Despenser.

Despenser, who has married a Clare and thereby gained control of Glamorgan on the Welsh border, becomes a target of the Marcher lords’ ire.

The Earl of Lancaster unites opposition against Despenser and maneuvers his exile.

Edward, furious, sends royal troops against the Marcher lords at Boroughbridge in 1322, defeating the rebel cavalry with dismounted men-at-arms and archers and afterwards executing Lancaster—whose title passes to his brother, Henry—and several of his associates.

Despenser returns to Edward’s side, and his allies help him to repeal the 1311 laws on the basis that they had been passed only by the nobles.