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
The Twelve of England sealed by the marriage of John I of Portugal and Philippa of Lancaster, daughter of John of Gaunt) and before the death of John the Gaunt in 1399. Narrowing the window further, it was probably sometime after 1389, when John of Gaunt returned to England from his failed Iberian campaign, and before the death of John of Gaunt's wife, the Duchess of Lancaster, Constance of Castile in 1394. The common date frequently cited is 1390. The Duchess's Castilian nationality may lend credence to such an event, and her twelve ladies-in-waiting were also, likely, Castilian rather than English, which may explain