John of Gaunt John of Gaunt John of Gaunt, Duke of Lancaster (6 March 13403 February 1399) was an English prince, military leader, and statesman. He was the third of the five sons of King Edward III of England who survived to adulthood. Due to his royal origin, advantageous marriages, and some generous land grants, Gaunt was one of the richest men of his era, and an influential figure during the reigns of both his father, Edward, and his nephew, Richard II. As Duke of Lancaster, he is the founder of the royal House of Lancaster, whose members would ascend to the throne
John of Gaunt dexter side of the shield (the left hand side as viewed), and the differenced English royal arms on the sinister; but in 1388, when he surrendered his claim, he reversed this marshalling, placing his own arms on the dexter, and those of Castile and León on the sinister. He thus continued to signal his alliance with the Castilian royal house, while abandoning any claim to the throne. There is, however, evidence that he may occasionally have used this second marshalling at earlier dates. In addition to his royal arms, Gaunt bore an alternative coat of "Sable, three ostrich feathers ermine".