Roger Mortimer: The Greatest Traitor Who Ruled as King

Written by Simon Williams

Roger Mortimer escaped the Tower of London, invaded England with Queen Isabella, and deposed Edward II in 1326, ruling the kingdom for four years before the teenage Edward III seized him at Nottingham Castle and ordered his execution at Tyburn in 1330.

Key Facts

• Full name: Roger Mortimer, 1st Earl of March
• Born: c. 1287, Wigmore, Herefordshire
• Died: 29 November 1330, Tyburn, London (executed by hanging)
• Title: 1st Earl of March (created 1328); Baron Mortimer of Wigmore
• Partner in exile: Queen Isabella of France (lover and co-conspirator from 1325)
• Key act: Led the first successful deposition of an anointed English king (Edward II, 1327)
• Overthrown by: Coup by Edward III at Nottingham Castle, October 1330
• Historical significance: Created the constitutional precedent for royal deposition, directly influencing the events of 1399

Roger Mortimer stands out in the history of medieval England not simply as a rebel or a lover, but as a man who briefly held the English crown in all but name. His story is one of the most dramatic of the fourteenth century: a fall from power, a dramatic escape from the Tower of London, a triumphant return, and an eventual execution ordered by the very king he had helped to raise.

Origins and Early Career

Roger Mortimer was born around 1287 into one of the most powerful Marcher lord families in England. The Mortimers held vast estates along the Welsh border, and Roger inherited that tradition of military command and political ambition. He served in Scotland and Ireland, proving himself a capable military commander, and by the reign of Edward II he had become one of the leading magnates of the realm.

Opposition to Edward II

Edward II's reign was defined by favouritism and political incompetence. His reliance first on Piers Gaveston and later on the Despensers alienated the powerful barons who expected to share in royal governance. Mortimer became a central figure in the baronial opposition. In 1321, he joined the coalition of lords that forced Edward to exile the Despensers.

But Edward recovered. The Despensers returned. In 1322, after the defeat of the barons at the Battle of Boroughbridge, Mortimer was captured. He was sentenced to death, but the sentence was commuted to life imprisonment in the Tower of London.

The Escape from the Tower

In August 1323, Roger Mortimer accomplished something almost without precedent: he escaped from the Tower of London. The details remain somewhat murky, but it appears his guards were drugged and he was lowered by rope from a window to waiting allies. He fled to France, where he found refuge at the court of Charles IV.

It was in France that he encountered Isabella, Queen of England, who had been sent to negotiate with her brother the French king. Their relationship became intimate, and together they formed the plan that would transform England.

The Invasion and Fall of Edward II

In September 1326, Mortimer and Isabella landed in Suffolk with a small invasion force. Edward II's support collapsed with remarkable speed. The Despensers were captured and executed. Edward II fled west and was eventually captured in Wales in November 1326.

Mortimer now effectively ruled England alongside Isabella. Edward II was imprisoned at Berkeley Castle and died there in September 1327 under circumstances that have been debated ever since. The official account was natural causes, but contemporaries and later historians have suspected murder, and Mortimer's role in whatever occurred remains a matter of historical controversy.

The Regency and the Acquisition of Power

The new king, Edward III, was fourteen years old. Real power lay with his mother and Mortimer. Mortimer accumulated titles, lands, and wealth at a rate that alarmed the nobility. He was created Earl of March in 1328, a new title signalling a claim to near-royal status.

The Treaty of Edinburgh in 1328, which recognised Scottish independence and Robert Bruce as king, was deeply unpopular in England and seen as a humiliation. It became known derisively as the Shameful Peace. Mortimer's handling of a subsequent rebellion by Henry of Lancaster, and the suspicious death of Edward II's brother the Earl of Kent, further eroded his support among the nobility.

The Coup at Nottingham Castle

Edward III endured Mortimer's dominance until he was ready to act. In October 1330, the young king and a group of allies entered Nottingham Castle through a secret passage and arrested Mortimer in Isabella's chamber. The speed and decisiveness of the act reflected how carefully it had been planned and how completely Mortimer had been caught off guard.

Mortimer was taken to London, tried before Parliament, and condemned to death. He was hanged at Tyburn in November 1330. He was around forty-three years old. Isabella was spared; Edward III treated his mother with respect despite her role in the regency, though she was effectively retired from political life.

Historical Legacy

Mortimer's reputation has fluctuated across the centuries. He was long cast as a villain, the adulterous usurper who destroyed a king and exploited a boy monarch. More recent assessments have placed him within the context of baronial politics and acknowledged his genuine ability as a military commander and administrator.

What is beyond dispute is the drama of his life. Few figures in medieval England rose so high so rapidly, or fell so completely. His escape from the Tower, his conquest of England with a foreign army, his years of dominance, and his sudden overthrow by the teenage king he had underestimated form a narrative that reads almost like fiction.

Roger Mortimer was the product of his age: an age when great lords expected to govern alongside their kings, when the line between legitimate counsel and usurpation was easily crossed, and when political survival required not just ambition but constant vigilance. He possessed the first in abundance. At the end, he lost the second.

To understand Mortimer fully, his story must be read alongside that of Queen Isabella of France, whose own trajectory from discarded queen to regent is one of the most remarkable in medieval history. For the broader context of Edward II's troubled reign, our article on Edward II traces the political crisis from its origins.

This article is part of the Notable Historical Figures series. Explore all articles at historiesandcastles.com/blogs/historical-figures.

Deepen Your Understanding

History rarely happens in isolation. The people, places, and events on this page are part of a much bigger story. The articles below explore the threads that connect to what you have just read.

→ Piers Gaveston: The Favourite Who Sparked a King's Downfall: The first of Edward II's great favourites; the baronial fury his execution generated created the political conditions Mortimer later exploited.

→ Hugh Despenser the Younger: The Ruthless Favourite Who Ruled England: The second favourite Mortimer helped bring down; his execution in 1326 was the first act of Mortimer and Isabella's regime.

→ Edward II: The King Who Lost Everything: The full account of the reign Mortimer helped end, tracing the political crises from Gaveston through the Despensers to the deposition of 1327.

→ Edward I: The King Who Built Castles to Crush Wales: The formidable father whose iron grip on power shaped the Marcher lord world Mortimer was born into, and whose death in 1307 set in motion the chaos that followed.

→ Tywin Lannister and Edward I: A Stark Comparison: The contrast between sustained, calculated authority and the collapse of governance under Edward II illuminates why Mortimer's story is both historically significant and narratively compelling.

People Also Ask

How did Roger Mortimer escape from the Tower of London?

In August 1323, Mortimer escaped in circumstances that remain partially obscure. The most detailed accounts suggest his guards were drugged during a feast, allowing him to break through a wall into a service passage before using a rope to descend the outer walls. Waiting allies helped him cross the Thames to a waiting boat. He reached France by September and found refuge at the court of Charles IV, where he would spend the next two years planning his return. The escape was one of the most audacious acts in the Tower's history.

What was the nature of Roger Mortimer's relationship with Queen Isabella?

Isabella had been sent to France by Edward II in 1325 to negotiate over English territories. There she encountered the exiled Mortimer, and the two became lovers and political partners, united by their shared opposition to the Despensers and Edward II's misrule. They gathered a mercenary force and invaded England in September 1326. Contemporaries were well aware of the relationship and regarded it with varying degrees of scandal; Edward III clearly knew of it but chose not to punish his mother after Mortimer's overthrow.

Why was Mortimer considered a tyrant by the English nobility?

After the deposition of Edward II, Mortimer governed effectively as regent for the teenage Edward III but showed little interest in sharing power. He ignored the young king and the Great Council, seizing vast estates for himself and his family. He held a Round Table tournament in 1328 conducted with near-royal ceremony, which contemporaries found deeply presumptuous. The Treaty of Edinburgh, which recognised Scottish independence, was widely seen as a national humiliation negotiated for Mortimer's personal advantage. The suspicious death of the Earl of Kent in 1330 convinced the nobility that no magnate was safe while he ruled.

How did Edward III overthrow Mortimer?

By October 1330, the eighteen-year-old Edward III had assembled a small group of loyal knights who shared his determination to end Mortimer's regency. They entered Nottingham Castle through a secret underground passage, bypassing the guards Mortimer had stationed at the gates specifically to prevent the king from acting independently. They arrested Mortimer in the chamber adjoining the queen's rooms. Isabella, by some accounts, pleaded for his life. Edward was unmoved. Mortimer was taken to London, tried before Parliament, and condemned to death without being permitted to speak in his own defence.

What were the charges against Roger Mortimer at his trial?

Mortimer faced several counts, including the seizure of royal power by surrounding the king with his own men, the murder of Edward II, and embezzlement of the royal treasury. He was also charged with the judicial murder of the Earl of Kent and with dishonourably negotiating the Treaty of Edinburgh. Unlike most men of his rank, he was denied the right to trial by his peers and was condemned to a commoner's death. He was hanged at Tyburn on 29 November 1330, the first major figure executed there.

What happened to the Mortimer family after Roger's execution?

The family's lands and titles were initially forfeited. Edward III later proved willing to restore the Mortimer name to those who served him loyally: Roger's grandson Edmund was restored to the Earldom of March in 1354. The Mortimer bloodline would eventually become politically central during the fifteenth century: Roger's descendants through the female line provided the House of York with its claim to the English throne, making the deposed traitor of 1330 an indirect ancestor of Edward IV and Richard III.

Primary Sources and Further Reading

• Mortimer, I. (2003) — The Greatest Traitor: The Life of Sir Roger Mortimer, 1st Earl of March, Ruler of England, 1327–1330, Pimlico. The definitive modern biography, drawing on extensive archival research to reconstruct Mortimer's career in full.
• Vita Edwardi Secundi — A near-contemporary chronicle providing the most detailed narrative of the political crisis from Edward II's reign through the baronial upheavals. Available in translation: Childs, W. (trans., 2005), Oxford Medieval Texts, Oxford University Press.
• Phillips, S. (2010) — Edward II, Yale English Monarchs series, Yale University Press. The standard modern biography of Edward II, essential context for Mortimer's career and the deposition.
• Haines, R. M. (2003) — King Edward II: His Life, His Reign, and Its Aftermath, 1284–1330, McGill-Queen's University Press. A thorough scholarly treatment of the reign and its aftermath, including the controversy over Edward II's death.
• Fryde, N. (1979) — The Tyranny and Fall of Edward II, 1321–1326, Cambridge University Press. Covers the Despenser regime and its collapse in detail, directly contextualising Mortimer's invasion and rise to power.

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