CP: Possibly she is dau. of Piers FitzHerbert, lord of the Honour of Brecknock.  DNB is sure of it...
___________________________________________________________________________

On 19th March 2007, John Ravilious produced more information that add to this idenification of Lucy:

“     The evidence I have in hand is as follows:

“A. Werthorp (Wiverthorpe), Yorks. was one of the holdings of the
FitzHerberts (later lords of Blaen Llyfni), and was to be found later
in the maritagium of Mary de Ros, wife of Sir William de Braose of
Bramber and Gower.”
The evidence that followed was clear-cut that Wiverthorpe had been in the FitzHerbert family.

We are now awaiting the reference that put Wiverthorpe into Mary de Ros’ maritagium.

In the menawhile I have made Lucy the dau. of Piers fitz Herbert as this seems too strong to omit.  Though watch this space!
___________________________________________________________________________