Why is it that Edward the Confessor is not seen as Edward the 1st?

He was half Norman and he was also revered as a saint by the Normans, but why is it that the line of kings (as in the 1st the 2nd etc) is rewritten when they seize the crown? I can understand why they would want to take Harold out of the equation (what with him "supposedly" stealing William the s throne) but England had the oldest Monarchy in Europe and most of these normans actualy claimed decent from those same kings to legalise their claims (it is a known fact they married into what was left of the Anglo Saxon nobility) so if this is the case why did they effectivly scrub what came before?