Sibyl of Falaise

Sibyl of Falaise (or Sibil de Falaise) was a kinswoman of King Henry I of England. She was possibly his illegitimate daughter or a niece, as the sources are unclear. Another possibility is that she may have been more distantly related to him instead. She married and had at least one daughter, although her husband's other children may possibly be her offspring also. Through her daughter, Sibyl was the grandmother of Reginald fitzUrse, one of the murderers of Thomas Becket.