Douglas Richardson's Magna Carta Ancestry mentions in passing that Philippe Bonville as the wife of William Grenville and daughter of John Bonville and Elizabeth FitzRoger .[1] Richardson gives no information about her descendants, but the Grenville lineage is well-established from other sources.

In a 2001 post at the soc.genealogy.medieval forum, Lois Staley questioned the accepted parentage of Philippa Bonville, advancing the possibility that Philippa was actually the daughter of John and Elizabeth Bonville's second son Thomas:

"Could Philippa's parents have been Thomas Bonville, son of John Bonville and Elizabeth fitz Roger, and his wife Leva Gorges, daughter of John Gorges?

"This Thomas Bonville died 11 Feb 1466, Leva died before 16 December 1461 when her IPM says 'Bonevile, Leva, who was the wife of Thomas, esq, daughter and heiress of John Gorge, esq Devon, Corn." 1 Edw IV Chancery: Inquisitions Post Mortem C 140/2/24. I have seen unsourced that he was married first to Joanna Poynings.

"Philippa married William Grenville, son of Theobald Grenville after 1428 MC 22-10. Philippa had traditionally been identified as the daughter of William Bonville and Margaret Grey of Ruthin. However in MC the identifaction was moved to John Bonville and Elizabeth fitz Roger. MC 22-10 says "Philippa received as her marriage portion the manors of Week St Mary, Swannacote and other tenements in the hundred of Stratton Cornwall." , vol. 9, pp. 84-86).

"Granville, which on my reading is proving to be incomplete, if not unreliable, has this to say about the marriage of Philippa and William Grenville: 'He is mentioned in a deed with Philippa, his second wife, a daughter of William, Lord bonville of Chuton, dated at Stowe 20th July 24 Henry VI [1446]. Lord Bonvill died possessed of the manors of Week St Mary, Swannacote, and other tenements in the hundred of Stratton in Cornwall, and the whole of this property came into William de Greynvill's possession by this marriage.'

"And this to date the marriage of Philippa and William as being after 12 May 1427: 'It appears from old records that he was twice married, and that Thomasine, daughter of John Cole, was his forst wife, as it should seen by indenture made at Bideford the Monday after the Feast of St John ante portam Latinam, 5th Henry VI [1427], between William de Greynevill and Thomasine his wife on the one part, and John Cole on the other part, which witnesseth that the aforesaid Thomasine had certain lands and tenements in Yllecombe and Hodesland, within the manor of Kilkhampton, of Sir John de Greynvill, Kt, deceased brother of the said William, whose heir he is by knight's service and doing suits to his courts and mill.'

"Granville is clearly not sure about Philippa's father, hence the query in brackets. Weis quotes directly from Granville on the tenements although Weis adds they came with her marriage which I can't see a source for.

"Now, Philippa and William Grenville had three children, Thomas, Ellena and Margery. Is it possible the first two were named after Philippa's parents? Thomas Grenville married Anne Courtenay and then Elizabeth Gorges which puts up a cosanganuity flag but as I don't know how Leva was related to Elizabeth, it may have been OK, or Philippa Bonville's mother may have been Joanna Poynings but she named her daughter after the woman who raised her.

"If Philippa is the daughter of Thomas Bonville she would have been born after about 1416, whereas if she is the dauther of John Bonville she must have been born before 1396 when he died."