• General Notes

  William Ferrers married Sibyl Marshal, one of the daughters and co-heirs of William Marshal, 1st Earl of Pembroke. They had seven daughters:
  
  Agnes Ferrers (died 11 May 1290), married William de Vesci.
  Isabel Ferrers (died before 26 November 1260), married (1) Gilbert Basset, of Wycombe, and (2) Reginald de Mohun
  Maud Ferrers (died 12 March 1298), married (1) Simon de Kyme, and (2) William de Vivonia (de Forz), and (3) Amaury IX of Rochechouart.
  Sibyl Ferrers, married Sir Francis or Franco de Bohun, an ancestor of Daniel Boone. (it is her aunt Sibyl, sister of William, who married John de Vipont, Lord of Appleby)
  Joan Ferrers (died 1267), married to:
  John de Mohun;
  Robert Aguillon
  Agatha Ferrers (died May 1306), married Hugh Mortimer, of Chelmarsh.
  Eleanor Ferrers (died 16 October 1274), married to:
  William de Vaux;
  Roger de Quincy, Earl of Winchester (m. abt. 1252);
  Roger de Leybourne

Details of Sybil's family with William de Ferrers (5th Earl of Derby)