Arthur I, Duke of Brittany
Arthur I (Breton: Arzhur 1añ[a]; French: Arthur 1er de Bretagne) (29 March 1187 – presumably 1203) was 4th Earl of Richmond and Duke of Brittany between 1196 and 1203. He was the posthumous son of Geoffrey II, Duke of Brittany, and Constance, Duchess of Brittany. His father, Geoffrey, was the son of Henry II, King of England.
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. Some of the ways that it is believed or rumored of how he would have been murdered would be that John had either drowned him in a lake or stabbed him to death when in a drunk fury.
Treaty of Le Goulet[edit]
The Treaty of Le Goulet was signed by the kings John of England and Philip 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, Philip recognised John as King of England as heir of his brother Richard I and thus formally abandoned any support for Arthur. John, meanwhile, recognised Philip as the suzerain of continental possessions of the Angevin Empire.
Philip 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.[b]
Succession[edit]
The mystery surrounding Arthur's death complicated his succession. This succession was presumably influenced by both King John and King Philip II.[c] There were no male heirs to the ducal crown and so his succession as duke was constrained to several choices among his sisters.
His 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.[d]