Her ancestry is unclear, with David Crouch stating she was a member of the de Lacy family.
[3] Talbot was present at the Easter court held by King Stephen at Westminster in 1136, along with a number of other nobles, magnates, and ecclesiastics.
[9] In October 1139, Talbot was once more in charge of Hereford and withstood an attack by Miles of Gloucester, at that time a supporter of King Stephen.
[11] He was joined in his siege efforts by Miles of Gloucester, who had switched sides and was then supporting Matilda.
[12] Talbot died in about 1140, and his lands passed to Sybil,[2] and her second husband, Josce de Dinan.
[14] The lands at Swanscombe were divided between Talbot's two nieces, Cecily and Agnes, the daughters of Sybil and Pain fitzJohn.
Cecily married first Roger of Hereford, son of Miles of Gloucester, and second William of Poitou and third Walter de Mayenne, but she had no children by any of her marriages and on her death in 1207, her lands passed to the heirs of her sister Agnes.