About Girard Tancred De Hautville
Girard Tancred de Hauteville was not the son of Richard II / Duke of Normandy!! Neither primary or secondary sources make any reference to "Girard Tancred de Hauteville" as a son of Richard II / Duke of Normandy by either of his wives or known mistresses.
The House of Hauteville is "said to be descended from Hiallt, a Norseman who settled in the Cotentin Peninsula and founded the village of Hialtus Villa (Hauteville) from which the family takes its name. From just which village of Hauteville (which may simply mean "high town") the family draws its name is hard to identify with certainty. Modern scholarship favours Hauteville - la - Guichard.....The first of the family well known to us is Tancred of Hauteville, the founder of the eponymous villa. He remained until his death (circa 1041) a minor baron of Normandy".
One notes that both "Girard Tancred de Hauteville" and Tancred Guiscard / Seigneur de Hauteville share both a common place of birth, albeit at different dates, and a common death date of 1041. It seems highly unusual that both a father and son would die in the same year. One also notes that the wife of Girard Tancred de Hauteville is indicated as "Fresende of Normandy", while the wife of Tancred Guiscard / Seigneur de Hauteville is indicated as "Fredesende de Hautville -- a variant of Fresende. Inasmuch as available primary and secondary sources do not provide solid birth and death dates for either Fresende or Fredesende, the discrepancy between the two is moot. Reasonable inference would strongly suggest that "Girard Tancred de Hauteville" and Tancred Guiscard / Seigneur de Hauteville are, in fact, one and the same person!!
SOURCE -- "Hauteville Family" / en.wikipedia.org / wiki / Hauteville_family