Philippa de Mortimer (1375-1401) (1375–1401) Parents Philippa, 5th Countess of Ulster Edmund Mortimer, 3rd Earl of March Children John FitzAlan Siblings Elizabeth Mortimer Roger Mortimer, 4th Earl of March Edmund Mortimer Partners Richard FitzAlan, 4th Earl of Arundel John Hastings, 3rd Earl of Pembroke Thomas Poynings, 5th Lord St. John of Basing