In your original post (copied above) you wrote: "recently I noticed
Wikipedia had: William Devereux, d. 1265 at Evesham as the son of a
daughter of Hugh Bigod, 3rd Earl of Norfolk, and Maud Marshal."
You have since linked a Wikipedia page that says "William Devereux was
born about 1244, the son of the powerful marcher lord, William Devereux
the Elder, and a daughter of Hugh Bigod, 3rd Earl of Norfolk, and Maud
Marshal". This man reportedly died in 1314.
So either there is another Wikipedia page saying what you originally
wrote or else this was accidentally misleading and you meant "William
Devereux, d. 1265 at Evesham as the husband [not son] of a daughter of
Hugh Bigod".
This William Devereux, who died at Evesham after a series of lawsuits
over his middling Marcher inheritance, son of a knight in the retinue of
William Marshal, was hardly in the socio-economic league of potential
husbands for daughters of earls. According to Brock Holden: "In 1238 he
brought an assize of mort d'ancestor against Walter de la Hide for 20s.
rent in Hide, while in 1241 he used the same action, this time against
the prior of Wormsley for 10 marks' rent in Holme Lacy. In the 1240s
William was apparently denying the canons of Wormsley rights of estover
in his woods at Lyonshall, the family seat. [para] In 1242 William was
embroiled in a dispute with Thomas de Fauconburg, canon of Hereford,
because Thomas claimed William was not upholding the agreement made
between William's father, Stephen, and Thomas's predecessor over a pond
and alder grove in Hereford. The following year he was a party in two
suits, one concerning land and another a mill. In 1244 William had to
secure a writ /non obstante/ from the king for the restoration of his
Norfolk manor of Wilby, which had been seized as /terra Normannorum/.
That same year the prior of the Hospitallers in England brought suit
against William concerning the unjust detaining of a charter (/de quadam
carta injuste detenta/), and one wonders if this charter concerned debts."
Your reading of "his uncle" as referring to the 4th earl of Norfolk as
uncle of the 5th earl rather than of William Devereux makes sense and
adequately answers the question you raised in the first place about the
tendentious Wikipedia assertion. There is little reason to hope that
this could be clarified in the original document, as pronouns are no
more specific in Latin than in English.
Peter Stewart