> But as you will notice Godfroi de Bouillon is now mentionned as
> Godfroi de Vere de Bouillon.
I've noticed the same thing in genealogies of other families. For some reason, an old form of the current surname crops up within the name itself. The Sinclairs and my family both share a common ancestor. However, in the version that we have, it does not carry any form of "st. clair" at all. ie. Gilbert de Corbeil is for some reason called something like Gilbert St. Clair de Corbeil in their version.
Not sure why people feel like they need to do that. As far as I know from my own family's example, our "surname" changed whenever we changed manors until just a few hundred years ago. Maybe the need to feel like they have a greater legitimacy in their claims?