Edward the Black Prince compelling Peter of Castile to flee from his kingdom, and in setting up his bastard brother, Henry of Trastámara, as king in his stead. Peter, who was in alliance with Edward III, sent messengers to the Black Prince asking his help, and on receiving a gracious answer at Corunna, set out at once, and arrived at Bayonne with his son and his three daughters. The prince met him at Capbreton, and rode with him to Bordeaux. Many of the prince's lords, both English and Gascon, were unwilling that he should espouse Peter's cause, but he declared that it was not
Edward the Black Prince he returned to England, leaving John in charge of Sir Walter Manny and three other knights. He accompanied his father to Calais on 9 October to assist at the liberation of King John and the ratification of the treaty. He rode with John to Boulogne, where he made his offering in the Church of the Virgin. He returned with King Edward to England at the beginning of November. On 10 October 1361 the prince, now in his 31st year, married his cousin Joan, countess of Kent, daughter of Edmund of Woodstock, Earl of Kent, younger son of Edward I, and