[--- . The inheritance of part of the Lacy estates by Sibylla's descendants indicates that one of her parents was a child of Walter de Lacy. Wightman says that Sibylla was the daughter of Hugh de Lacy, without specifying a primary source which confirms his statement, although he concedes that "it has frequently been assumed that [Hugh] died childless". The difficulty is that Sibylla's descendants inherited only part of the Lacy estates, as indicated by the charter dated to [Dec 1137/May 1138] under which King Stephen only referred to Sibylla's dowry as quoted below, whereas Sibylla would presumably have been sole heiress if Hugh had been her father. Rivalry between Sibylla's heirs and Gilbert de Lacy concerning the succession to the Lacy estates in England is indicated by an agreement dated to [1147/49] between Roger Earl of Hereford (husband of Sibylla's older daughter) and William Earl of Gloucester to combine forces against Gilbert de Lacy. This suggests that their respective claims to the estates were of equal weight, and that the two were cousins not brother and sister. The Complete Peerage discusses the theory that this person was the wife of Geoffrey [I] Talbot (named Agnes in other sources). The argument centres around Gauthier de Mayenne, third husband of Cecily daughter of this person's daughter Sibylla de Lacy, recording that in 1166 he held land previously held by Geoffrey [II] Talbot: "Walterus de Meduana" confirmed to King Henry II that he held "in capite...xx milites" in Kent which "Galfridus Tallebot" had held on the death of King Henry I, dated 1166. Some family relationship between Geoffrey [II] Talbot and the Lacy family is shown by the Gesta Stephani Regis which records that "Galfridus…Taleboth cognatus…Gislebertus de Laceio" was captured by King Stephen's forces, dated to [1139/40]. Keats-Rohan says that the wife of Geoffrey [I] Talbot "used erroneously to be identified as a de Lacy" but that in fact she was "possibly a daughter of Helto" (dapifer, recorded in Domesday Book as holding Swanscombe, Kent from Odo Bishop of Bayeux), and in a later sentence suggests that the connection between the Talbot and Lucy families would be explained if "Adeline or Adelisa, wife of Hugh de Lacy (d.a.1115), was the daughter of Geoffrey and Agnes". From a chronological point of view, it does not appear ideal for Sibylla de Lacy (married firstly "before ") to have been the daughter of Geoffroy [I] Talbot (born "[1050/65]?").
One child: Sibylla. 1
de Lacy married.