Millicent de Ferrers Peerage person ID=405470 Parents Sibyl de Braose William de Ferrers, 3rd Earl of Derby Children Sibyl Mortimer Julian ferch Roger Mortimer unknown daughter de Mortimer Hugh de Mortimer Joane de Mortimer Siblings William de Ferrers, 4th Earl of Derby Petronell de Ferrers Agatha de Ferrers Walkelin de Derby Partners Roger Mortimer of Wigmore