William de Burgo Montaigne, {Fictional}

Not the same as William, Count of Mortain

https://www.geni.com/discussions/223151?msg=1436673

Some 17th, 18 and 19th Century genealogists created a completely fictitious family tree for William and Hubert de Burgh, linking in William Fitz Aldelm, Robert of Mortain, Charlemagne et al. The whole theory was demolished by JH Round in "Feudal England" (1909), and there is a further discussion in Clarence Ellis's "Hubert de Burgh A Study in Constancy" (1952). All academic papers on the de Burgh family of Norfolk accept that the family was so minor that we can't even be confident as to who the father of William and Hubert de Burgh was.