When Eleanor's brother, Gilbert, was killed in 1314 at the Battle of Bannockburn, she unexpectedly became one of the three co-heiresses to the rich Gloucester earldom, and in her right, Hugh inherited Glamorgan and other properties.

Eleanor was also the niece of the new king, Edward II of England, and this connection brought Despenser closer to the English royal court.

Eager for power and wealth, Despenser seized Tonbridge Castle in 1315, after his brother-in-law's death under the misapprehension that it belonged to his mother-in-law; he relinquished it on discovering that the rightful owner was, in fact, the Archbishop of Canterbury.

Finally the barons took action against King Edward and, at the beseeching of Queen Isabella, forced Despenser and his father into exile in August 1321.

With the main baronial opposition leaderless and weak, having been defeated at the Battle of Boroughbridge, and Edward willing to let them do as they pleased, the Despensers were left unchecked.

Both he and his father were accused of murdering Llywelyn Bren in 1318 while the Welshman was being held hostage in what was characterised by contemporaries as an extrajudicial killing,[12] "conspiring together to exercise a jurisdiction which they could not lawfully have".

While Isabella was in France to negotiate between her husband and the French king, she formed an alliance with Roger Mortimer and began planning an invasion of England, which ultimately came to fruition in September 1326.

Their forces numbered only about 1,500 mercenaries to begin with, but the majority of the nobility rallied to them throughout September and October, preferring to stand with them rather than Edward and the hated Despensers.

"[19] The prisoners were crowned with nettles to symbolise the "crime of accroaching royal power",[22] while their surcoats bore "their coats of arms reversed",[19] to proclaim their "treachery".

[22] Despenser's "tunic bore a Latin verse from the New Testament: Quid gloriaris in malicia qui potens est in iniquitate?

The number of aggrieved parties meant that Despenser was certain to be quartered: every lord wanted a piece to show their followers that they had exacted revenge.

"[19] Trussell declared that he had been "ajudged a traitor and an enemy of the realm",[24] and read out the "exhaustingly long"[21] list of charges against him, including: breaking the terms of exile, breaching Magna Carta and the Ordinances of 1311, killing, imprisoning and tyrannizing the great and good of the realm, causing the king to fight in Scotland at the cost of thousands of men's lives, usurping royal authority and attempting to fund the destruction of Queen Isabella and her son Duke Edward while they were in France.

[25] He was subsequently "roped to four horses - not just the usual two - and dragged through the city to the walls of his own castle"[25] to "a specially made 50-foot gallows, designed to make punishment visible to everyone in the town.

"[25] In 14th century historian Jean Froissart's account of his execution, Despenser was tied firmly to a ladder and his genitals sliced off and burned while he was still conscious.

[26] Froissart (or, rather, Jean le Bel's chronicle, on which he relied) is the only source to mention this; other contemporary accounts state that Despenser was hanged, drawn and quartered, which did not usually involve emasculation.

"[25] Four years later, in December 1330, his widow was given permission to gather and bury Despenser's remains at the family's Gloucestershire estate,[3] but only the head, a thigh bone and a few vertebrae were returned to her.

The skeleton, which was first uncovered during archaeological work in the 1970s, appeared to be that of a victim of a drawing and quartering as it had been beheaded and chopped into several pieces with a sharp blade, suggesting a ritual killing.

[29] The numerous accusations against the younger Despenser at the time of his execution have never been the subject of close critical scrutiny, although Roy Martin Haines called them "ingenuous" and noted their propagandistic nature.

Despenser also appears as a character in Maurice Druon's historical fiction series Les Rois maudits, along with its television adaptations.