Duke of Aquitaine House of Valois claimed supremacy over Aquitaine. In 1360, both sides signed the Treaty of Bretigny, in which Edward renounced the French crown but remained sovereign Lord of Aquitaine (rather than merely duke). However, when the treaty was broken in 1369, both these English claims and the war resumed. In 1362, King Edward III, as Lord of Aquitaine, made his eldest son Edward, Prince of Wales, Prince of Aquitaine. In 1390, King Richard II, son of Edward the Black Prince appointed his uncle John of Gaunt Duke of Aquitaine. This grant expired upon the Duke's death, and the dukedom reverted
Edward the Black Prince differenced royal arms. His younger brother, John of Gaunt, used a similar shield on which the ostrich feathers were ermine. Edward's "shield for peace" is believed to have inspired the badge of three ostrich feathers used by later Princes of Wales. Edward married his cousin, Joan, Countess of Kent (1328–1385), on 10 October 1361. She was the daughter and heiress of Edmund, Earl of Kent, the younger son of King Edward I by his second wife Margaret of France. They had two sons, both born in Aquitaine: From his marriage to Joan, he also became stepfather to her children by