Cecilia of Normandy  Cecilia of Normandy (or Cecily; c. 1056 – 30 July 1126) is thought to be the eldest daughter of William the Conqueror and Matilda of Flanders. Her brothers were kings William II and Henry I of England. She was very close to her other brother, Robert Curthose, and was educated by the abbess Matilda. Cecilia 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 July 1126 in Caen, France. She was buried within the abbey walls. Her tomb is walled up without any opening being left through which it can be discovered. Her father was also buried in Caen.