He [William de Briouze] married, in or before 1150, Bertha, 2nd sister and coheir of William of Hereford being daughter of Miles of Gloucester, 1st Earl of Gloucester. Sheriff of Hereford, Easter 1173-75, at which earlier date probably he already possessed the Lordship of Over Gwent. He was living in 1179. [Complete Peerage I:21-2, XIV:6, (transcribed by Dave Utzinger)]
Note: The above text "1st Earl of Gloucester", which was part of a correction in CP XIV:6, is a mistake; Miles was Earl of Hereford.