Sibyl Marshal Peerage person ID=42677 (b. 1201) Parents Isabel de Clare, 4th Countess of Pembroke William Marshal, 1st Earl of Pembroke Children Isabel Ferrers Agnes Ferrers Sibyl de Ferrers Maud Ferrers Joan de Ferrers Agatha Ferrers Alianore de Ferrers Siblings Maud Marshal Isabel Marshal Joan Marshal William Marshal, 2nd Earl of Pembroke Gilbert Marshal, 4th Earl of Pembroke Anselm Marshal, 6th Earl of Pembroke Eva Marshal Richard Marshal, 3rd Earl of Pembroke Walter Marshal, 5th Earl of Pembroke Partners William de Ferrers, 5th Earl of Derby