The duchy originated in the desire of Henry III to provide for his youngest son Edmund Crouchback, after the failure of a scheme to make him king of Sicily. He was granted many of the estates of Simon de Montfort, killed at Evesham, and in 1267 was given all the royal estates in Lancashire, assuming the title of earl. Edmund's grandson, Henry of Grosmont, was created duke by Edward III in 1351, with considerable palatine powers. Henry left a daughter who married John of Gaunt, Edward III's younger son. When John's son Henry seized the throne as Henry IV in 1399, the dukedom of Lancaster was merged with the crown.
Subjects: British History.