A Genealogical Companion and Key to the History of England Consisting of Copious Genealogical Details of the British Sovereigns, p. 62, by George Fisher of Swaffham, Norfolk, pub. 1832 by Simkin & Marshall, which states: "A Natural Son of William I: William de Peverel, begotten on Maud, daughter to Ingelric, a noble Saxon, one of the most celebrated beauties of the age, who afterwards marrying Ranulph de Peverel, that surname was attached to the son of the Conqueror." (https://play.google.com/store/books/details?id=H78IAQAAMAAJ&rdid=book-H78IAQAAMAAJ&rdot=1)
