, , , , ,

Arthur I (March 29, 1187 – presumably April 1203) was 4th Earl of Richmond and Duke of Brittany between 1196 and 1203.

Early life
Arthur was born in 1187, the son of Duchess Constance of Brittany and Duke Geoffrey II of Brittany, who died before he was born. As an infant, Arthur was second in line to the succession of his paternal grandfather King Henry II of England, after his uncle Richard. King Henry died when Arthur was 2 years old, and Richard I became the new king in his place.

In the 1160s, Henry II began to alter his policy of indirect rule in Brittany and to exert more direct control. Henry had been at war with Conan IV, Duke of Brittany. Local Breton nobles rebelled against Conan, so Conan sought Henry II’s help.

In 1164, Henry intervened to seize lands along the border of Brittany and Normandy and, in 1166, he invaded Brittany to punish the local barons. Henry then forced Duke Conan IV to abdicate as duke and to give Brittany to his five-year-old daughter, Constance, who was handed over and betrothed to Henry’s son Geoffrey. This arrangement was quite unusual in terms of medieval law, as Conan might have had sons who could have legitimately inherited the duchy.

Geoffrey and Constance eventually married, in July 1181, and Geoffrey became Geoffrey II, Duke of Brittany
Via the law Jure uxoris (a Latin phrase meaning “by right of (his) wife”) describes a title of nobility used by a man because his wife holds the office or title suo jure (“in her own right”). Similarly, the husband of an heiress could become the legal possessor of her lands.

In 1190 Arthur was designated heir to the throne of England and its French territory by his uncle, Richard I, the intent being that Arthur would succeed Richard in preference to Richard’s younger brother John. Nothing is recorded of Arthur after his incarceration in Rouen Castle in 1203, and while his precise fate is unknown, it is generally believed he was killed by John.

While Richard was away on the Third Crusade, Arthur’s mother Constance sought to make the Duchy of Brittany more independent. On November 11, 1190, Arthur was named as Richard’s heir presumptive and was betrothed to a daughter of King Tancred of Sicily as part of their treaty. However, Holy Roman Emperor Heinrich VI conquered the Kingdom of Sicily in 1194, so the betrothal of Arthur came to nothing.

A marriage plan, originally aiming to establish an alliance between King Richard and King Philippe II of France to marry Arthur’s elder sister Eleanor to Philippe’s son Louis also failed.

In 1196, Constance had the young Arthur proclaimed Duke of Brittany and her co-ruler as a child of nine years. The same year, Richard summoned Arthur, as well as Arthur’s mother, Constance, to Normandy, but Ranulf de Blondeville, 6th Earl of Chester, stepfather of Arthur, abducted Constance. Richard marched to Brittany to rescue Arthur, who was then secretly carried to France to be brought up with Louis.

When Richard died on April 6, 1199, on his deathbed he proclaimed his brother John as his heir, fearing Arthur was too young to look after the throne. Arthur was only twelve years old at the time and under the influence of the French king.

Arthur of Brittany pays homage to King Philippe II of France

John immediately claimed the throne of England, but much of the French nobility were resentful at recognising him as their overlord. They preferred Arthur, who declared himself vassal of Philippe II.

Philippe II recognised Arthur’s right to Anjou, Maine, and Poitou. Upon Richard’s death Arthur led a force to Anjou and Maine. From April 18, he styled himself as Duke of Brittany, Count of Anjou and Earl of Richmond.

On September 18, John persuaded the seneschal of Anjou, William des Roches, to defect, claiming Arthur would be a Capetian puppet. Four days later William took Arthur and Constance prisoners to Le Mans. Viscount Aimery, the seneschal appointed by John, took Arthur and Constance and fled the court to Angers, and later the court of Philippe II.

Treaty of Le Goulet

The Treaty of Le Goulet was signed by the kings John of England and Philippe II of France in May 1200 and meant to settle once and for all the claims the Norman kings of England had as Norman dukes on French lands, including, at least for a time, Brittany.

Under the terms of the treaty, Philippe II recognised John as King of England as heir of his brother Richard I and thus formally abandoned any support for Arthur. John, meanwhile, recognised Philippe II as the suzerain of continental possessions of the Angevin Empire.

Philippe II had previously recognised John as suzerain of Anjou and the Duchy of Brittany, but with this he extorted 20,000 marks sterling in payment for recognition of John’s sovereignty of Brittany.

Battle against John of England

After the signing of the Treaty of Le Goulet, and feeling offended by Philippe II, Arthur fled to John, his uncle, and was treated kindly, at least initially. However, he later became suspicious of John and fled back to Angers. Some unidentified source said that in April 1202, Arthur was again betrothed, this time to Marie of France, a daughter of Philippe II and Agnes of Andechs-Merania.

After his return to France, and with the support of Philippe II, Arthur embarked on a campaign in Normandy against John in 1202. Poitou revolted in support of Arthur. The Duke of Brittany besieged his grandmother, Eleanor of Aquitaine, John’s mother, in the Château de Mirebeau. John marched on Mirebeau, taking Arthur by surprise on July 31, 1202. Arthur was captured by John’s barons on August 1, and imprisoned in the Château de Falaise in Falaise, Normandy.

Imprisonment and disappearance

Arthur was guarded by Hubert de Burgh at the Chateau de Falaise. According to contemporaneous chronicler Ralph of Coggeshall, John ordered two of his servants to blind and castrate the duke. De Burgh could not bring himself to let Arthur be mutilated.

Fearful of John, de Burgh leaked news that Arthur had died of natural causes. This news infuriated Brittany, who suspected that Arthur had been murdered. The following year Arthur was transferred to Rouen, under the charge of William de Braose. Arthur vanished in April 1203, in the background of several military victories by Philippe II of France against King John.

Arthur’s disappearance gave rise to various stories. One account was that Arthur’s gaolers feared to harm him, and so he was murdered by John directly and his body dumped in the Seine. The Margam Annals provide the following account of Arthur’s death:

After King John had captured Arthur and kept him alive in prison for some time, at length, in the castle of Rouen, after dinner on the Thursday before Easter, when he was drunk and possessed by the devil [‘ebrius et daemonio plenus’], he slew him with his own hand, and tying a heavy stone to the body cast it into the Seine. It was discovered by a fisherman in his net, and being dragged to the bank and recognized, was taken for secret burial, in fear of the tyrant, to the priory of Bec called Notre Dame de Pres.

William de Braose is also rumoured to have murdered Arthur. After the young man’s disappearance, he rose high in John’s favour receiving new lands and titles in the Welsh Marches. Many years after Arthur’s disappearance, and just prior to a conflict with King John, de Braose’s wife Maud de Braose accused the king of murdering Arthur.

Not only the Bretons, but even Philippe II, were ignorant of what actually happened, and whether Arthur was alive or dead. Whatever his fate, Arthur left no known issue. William promised to direct the attack of Mirebeau on condition he was consulted on the fate of Arthur, but John broke the promise, causing him to leave John along with Aimeri of Thouars and siege Angers.


The mystery surrounding Arthur’s death complicated his succession. This succession was presumably influenced by both King John and King Philippe II. There were no male heirs to the ducal crown and so his succession as duke was constrained to several choices among his sisters.

Arthur’s sister Eleanor, the ‘Fair Maid of Brittany’, was also King John’s prisoner. Eleanor also presented a complicating factor, if not a threat, to John’s succession plans as King of England.

While permitted by John to succeed Richmond and claim her rights to Brittany, she remained imprisoned for the rest of her life, through the reign of John’s actual successor, his son Henry III of England.

While imprisoned, she never married and had no issue. Her imprisonment and the fact that she was located in England made it impossible for her to reign as hereditary Duchess of Brittany.

Arthur I was succeeded by his half-sister, Alix of Thouars, the daughter of Constance and her third husband Guy of Thouars.