Edward the Black Prince of Cornwall in 1337. He was guardian of the kingdom in his father's absence in 1338, 1340, and 1342. He was created Prince of Wales in 1343 and knighted by his father at La Hogne in 1346. In 1346 Prince Edward commanded the vanguard at the Battle of Crécy, his father intentionally leaving him to win the battle. He took part in Edward III's 1349 Calais expedition. In 1355 he was appointed the king's lieutenant in Gascony, and ordered to lead an army into Aquitaine on a chevauchée, during which he pillaged Avignonet and Castelnaudary, sacked Carcassonne, and plundered Narbonne.
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