What is XXX's brothers name?
Elizabeth Mortimer
Elizabeth Mortimer was born at Usk, Monmouthshire, Wales on 12 or 13 February 1371, the eldest daughter of Edmund Mortimer, 3rd Earl of March, and his wife, Philippa, the only child of Lionel, 1st Duke of Clarence, and Elizabeth de Burgh, Countess of Ulster.
Edmund Mortimer