The House of Clifford, Chapter 5: Much controversy surrounds the identity of
the Mother of William, for Rosamund was not the king's only mistress, though
there are many who believe she was. Those who dispute Rosamund's claim base
their case on the disparity in the ages of all concerned, but there is other
evidence as well which can not be ignored. Unfortunately, the records date
neither the birth of Rosamund nor that of her father, or her reputed sons.
Documents also indicate an Ida, and an Ykenai as his mother. Died on Crusade.