Henry I with Sybil Corbet
Lady Sybilla Corbet of Alcester was born in 1077 in Alcester in Warwickshire. She married Herbert FitzHerbert, son of Herbert 'the Chamberlain' of Winchester and Emma de Blois. She died after 1157 and was also known as Adela (or Lucia) Corbet. Sybil was definitely mother of Sybil and Rainald, possibly also of William and Rohese. Some sources suggest that there was another daughter by this relationship, Gundred, but it appears that she was thought as such because she was a sister of Reginald de Dunstanville but it appears that that was another person of that name who was not related to this family.
1. Sybilla de Normandy, married Alexander I of Scotland.
2. William Constable, born before 1105. Married Alice (Constable); died after 1187.
3. Reginald de Dunstanville, 1st Earl of Cornwall.
4. Gundred of England (1114–46), married 1130 Henry de la Pomeroy, son of Joscelin de la Pomerai.
5. Rohese of England, born 1114; married William de Tracy (b. 1040 in Normandy, France d. 1110 in Barnstaple, Devon, England)son of Turgisus de Tracy. They married in 1075. They had four children 1)Turgisus II de Tracy b. 1066, 2) Henry de Tracy b. 1068, 3) Gieva de Tracy b. 1068 d. 1100, 4)Henry of Barnstaple Tracy b. 1070 d.1170.
[G. E. Cokayne, in his Complete Peerage, Vol. XI, Appendix D pps 105-121 attemps to elucidate Henry I's illegiimate children. For Mistress Sybil Corbet, he indicates that Rohese married Henry de la Pomerai [ibid.:119]. In any case, the dates concerning Rohese in the above article are difficult to reconcile on face value, her purported children having seemingly been born before their mother, and also before the date of her mother's purported marriage.]
Sybilla Corbet 
