Arthur I, Duke of Brittany
| Arthur I | |
|---|---|
Arthur as portrayed in a genealogical roll in the British Library | |
| Duke of Brittany | |
| Reign | 1196–1203 |
| Predecessor | Constance |
| Successor | Alix |
| Co-rulers |
|
| Count of Anjou | |
| Reign | 1199–1203 |
| Predecessor | Richard the Lionheart |
| Successor | John Tristan |
| Born | 29 March 1187 Nantes, Brittany |
| Died | Disappeared 1203 (aged 15–16) |
| House | Plantagenet |
| Father | Geoffrey of England |
| Mother | Constance, Duchess of Brittany |
Arthur I (Breton: Arzhur; 29 March 1187 – presumably 1203) was 4th Earl of Richmond and Duke of Brittany between 1196 and 1203. He was the son of Duchess Constance of Brittany, born posthumously to Constance's first husband, Duke Geoffrey II. Through Geoffrey, Arthur was the grandson of King Henry II of England and Duchess Eleanor of Aquitaine, and the nephew of the English kings Richard I and John.
In 1190, Arthur, whose father had died, was arguably designated heir to the throne of England and its French territory, but as he was dying in 1199, Richard I named John, his youngest brother, heir to the throne, as Arthur was still just a child. Philip II of France thought to make use of a potential succession crisis in England and Brittany and for a while Arthur joined him.
Nothing is recorded of Arthur after his imprisonment by John in Rouen Castle in 1203. While his precise fate is unknown, it is generally believed John killed him.