Sibyl Marshal Lady of Kildare, Countess of Derby 748,1034
- Born: 1201, Pembroke, Pembrokeshire, Wales 1033,1034
- Marriage (1): William de Ferrers III Fifth Earl of Derby
- Died: 27 Apr 1245, Pembroke, Pembrokeshire, Wales at age 44 1033,1034
Noted events in her life were:
• Children. 748,1034 William and Sibel had seven daughters.
Sibyl married William de Ferrers III Fifth Earl of Derby, son of William de Ferrers Fourth Earl of Derby and Agnes de Keveliock Lady of Chartley. (William de Ferrers III Fifth Earl of Derby was born in 1193 in Derbyshire, England,1180 died on 28 Mar 1254 in Evington, Leicestershire, England 1180,1182 and was buried in Marevale Abbey, Warwickshire, England 1180.)