Note: CP has William as Agnes's 1st husband, and her 2nd husband as Piers de Brus. This has been changed, according to a review of the evidence as indicated by postings to soc.genealogy.medieval. See notes under Agnes.
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[WILLIAM DE ROUMARE, called Helie, son and heir. He joined with his parents in the foundation of Revesby. As Willelmus puer, filius comitis, he attested one of his father's charters. He made a grant circa 1150, using an equestrian seal, and was a benefactor to Bardney. After his death his father made a grant to Crowland "for the absolution of the soul of William my son, whose household had laid violent hands on the abbot himself in time of war," so that the son William came under censure. He married Agnes, 4th daughter of Stephen, COUNT OFAuMALE. He died v.p., in 1151, and is said to have been buried at Revesby. His widow married Piers DE BRUS.] [Complete Peerage VII:670, (transcribed by Dave Utzinger)]