Arthur I, Duke of Brittany

Arthur I
Arthur of Brittany as portrayed in a genealogical roll in the British Library
Duke of Brittany
Reign	1196–1203
Predecessor	Constance
Successor	Alix
Co-ruler	Constance (1196–1201)
Count of Anjou
Reign	1199–1203
Predecessor	Richard I of England
Successor	John Tristan
Born	29 March 1187 Nantes, Brittany
Died	presumed c. 1203 (aged 15–16)
House	Plantagenet
Father	Geoffrey II, Duke of Brittany
Mother	Constance, Duchess 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.
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