|SOME NOTES ON MEDIEVAL ENGLISH GENEALOGY|
Volume 4, page 120:
He [Sir Edmund Deincourt, Lord Deincourt (d. 1326/7)] m. Isabel, da. of Sir Reynold DE MOHUN, of Dunster, Somerset,(b) by his 2nd wife, Isabel, da. of William (DE FERRERS), EARL OF DERBY.(b)
Extracts, by St. George, from the Mohun Cartulary, f. 37v.
The issue of Isabel de Ferrers had certainly failed by April 1327, when an inquisition was taken after the death of John Meriet, who had married her granddaughter. But at this time at least two of Edmund's children were alive or had surviving issue (his son John and his daughter Margaret - see Willoughby, volume 12, part 2, page 658). Clearly, either his wife Isabel was not the daughter of Isabel de Ferrers, or he had another wife who was the mother of these children.
[Peter Stewart pointed out this contradiction in May 2001. The problem was also discussed in January 2002 by Douglas Richardson, Cris Nash and Rosie Bevan.]