Arthur, duke of Brittany (1187–1203?) was the posthumous son of Geoffrey Plantagenet and Constance, Duchess of Brittany. His uncle, the childless King Richard I of England, named Arthur his heir in 1191. However, after Richard's death, his brother John took the throne. Arthur was captured in France by the forces of King John and mysteriously disappeared. Shakespeare wrote some of his most emotional speeches for young Arthur in captivity.