Eleanor, Fair Maid of Brittany (b. 1184)
Eleanor Fair Maid of Brittany (c. 1184 – 10 August 1241), also known as Damsel of Brittany, Pearl of Brittany, or Beauty of Brittany, was the eldest daughter of Geoffrey II, Duke of Brittany, the fourth son of King Henry II of England, and Constance, Duchess of Brittany. After the presumed death in 1203 of her imprisoned younger brother, Arthur, she was heiress to vast lands including England, Anjou, Aquitaine, and Brittany, realms where the Salic Law barring the accession of females did not apply. Her uncle John, King of England was the fifth son of Henry II, and Eleanor inherited Arthur's claim to the throne as the child of John's elder brother Geoffrey. Thus she posed a potential threat to John, and following his death in 1216, equally to her cousin, Henry III of England; thus, having been put in prison in 1202, she was never released. As a prisoner she was also unable to press her claim to the Duchy of Brittany as her brother's heiress.

Like Empress Matilda and Elizabeth of York, her claim to the English throne gained little support from the barons, due to the expectation that the monarch should be male, despite legal provision for a female monarch. Some historians have commented that her imprisonment was "the most unjustifiable act of King John".