|SOME NOTES ON MEDIEVAL ENGLISH GENEALOGY|
Volume 10, page 402:
WILLIAM (HERBERT), EARL OF PEMBROKE and LORD HERBERT [d. 1491], only s. and h. [of William Herbert, Earl of Pembroke (d. 1469)]
Complete Peerage, volume 6, p. 442, note a, mentions Sir George Herbert, a second son of William, the first earl (d. 1469), and says that his great grandson, Sir William Herbert, died in 1592/3.
[This contradiction was pointed out by Adrian Channing and further discussed by Tim Powys-Lybbe, in February 2002.]