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
Edward II of England the Count of Flanders, but this too failed after it was blocked by King Philip IV of France. Between 1297 and 1298, Edward was left as regent in charge of England while the king campaigned in Flanders against Philip IV, who had occupied part of the English king's lands in Gascony. On his return, Edward I signed a peace treaty, under which he took Philip's sister, Margaret, as his wife and agreed that Prince Edward would in due course marry Philip's daughter, Isabella, who was then only two years old. In theory, this marriage would mean that the disputed Duchy