I think there can be little doubt that Herfastus "the Dane" was the father
of Gunnora, wife of Rich. I., Duke of Normandy; of Aveline, wife of
Osbernus de Bolebec, Lord of Bolbec and Count of Longueville; and of Weira,
wife of Turolf de Pont Audomere. The brother of these three sisters was
another Herfastus, Abbot of St. Evrau; who was the father of Osbernus de
Crepon, Steward of the Household, and Sewer to the Conqueror.