Guy De Beaufort 
Guy De was born about 1195. Guy De's father was Aleaume De Beaufort and his mother is Athalie Marguerite De Brimeu. His paternal grandparents are Baudouin I De Beaufort and Agnes De Rosney De Beaumez. He was an only child. He died in 1250.General Notes
SOURCES: LDS FHL Ancestal File # (familysearch.org)
"Ancestors/Descendants of Royal Lines" (Contributors: Manuel Abranches de Soveral, Reynaud de Paysac, F.L. Jacquier <Genealogy of Lewis Carroll, Justin Swanstrom, The Royal Families of England Scotland & Wales by Burkes Peerage; Debrett's Peerage & Baronage; Table of descendants French Canadian Genealogical Society; Families of Monfort-sur-Risle & Bertrand de Bricquebec; The Dukes of Normandy, XXXXI, Paul Leportier, Claude Barret; Irish Catholic Encyclopedia>, H.R. Moser <Burke Peerage>, L. Orlandini, O.Guionneau, L.B. de Rouge, E. Polti, A.Terlinden <Genealogy of the existing British Peerage, 1842>, L. Gustavsson, C. Cheneaux, E. Lodge, S. Bontron <Brian Tompsett>, R. Dewkinandan, H. de la Villarmois, C. Donadello; Scevole de Livonniere, H. de la Villarmois, I. Flatmoen)... http://geneastar.org.
Guy De and Marie Alix D' were married in a religious ceremony in 1218. They had a son named Jean I De.