Agnes Ferrers Peerage person ID=42675 (1220–1290) Parents Sibyl Marshal William de Ferrers, 5th Earl of Derby Children William de Vesci John de Vesci Juliana de Vesci Siblings Alianore de Ferrers Joan de Ferrers Maud Ferrers Isabel Ferrers Agatha Ferrers Sibyl de Ferrers Elizabeth Ferrers Robert de Ferrers, 6th Earl of Derby William Ferrers Agnes de Ferrers Joan de Ferrers Partners William de Vesci