Apologies in advance if this question has been considered
earlier in the Discussion Group.
According to Givens-Wilson/Curteis in "The Royal Bastards of Medieval
England" William I was faithful to his wife, Matilda.
Alison Weir in "Britain's Royal Families The Complete Genealogy" lists no
illegitimate issue for William the Conqueror.
Best Regards, Leslie Hauck
Leslie