Cecilia was thought to be the eldest daughter of William I of England and Matilda of Flanders, she was entered into the Abbey of Caen at a young age by her parents. She became Abbess of Holy Trinity in 1112. Cecilia died on 30 Jul 1126 and was buried within the abbey walls. Her tomb is walled up without any opening being left through which it can be discovered.

References

• Lives of the Princesses of England from the Norman Conquest - Mary Anne Everett Green Pages 1-13