The '''Duchy of Lancaster''' derives from an earldom created by [[Henry III]] for his younger son, Edmund, and enlarged by many of the estates of [[Simon de Montfort]] after his death at [[Evesham]]. Edmund’s grandson, Henry Grosmont, a friend and supporter of [[Edward III]], was created a duke in 1351, and the duchy with its vast estates and income came to [[John of Gaunt]] through his marriage to Henry’s only child, Blanche. | The '''Duchy of Lancaster''' derives from an earldom created by [[Henry III]] for his younger son, Edmund, and enlarged by many of the estates of [[Simon de Montfort]] after his death at [[Evesham]]. Edmund’s grandson, Henry Grosmont, a friend and supporter of [[Edward III]], was created a duke in 1351, and the duchy with its vast estates and income came to [[John of Gaunt]] through his marriage to Henry’s only child, Blanche. |