Geoffroi I De Chateaumur 
Geoffroi I De was born about 1170. Geoffroi I De's father was Acfred III De Chateaumur. His paternal grandfather was Acfred II De Chateaumur. He was an only child. He died about 1236.General Notes
SOURCES: LDS FHL Ancestal File # (familysearch.org)
"Ancestors/Descendants of Royal Lines" (Contributors: Manuel Abranches de Soveral, Reynaud de Paysac, F.L. J P de Palmas <Aurejac et Tournemire; Frankish line>, 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>, 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.
He had a biological son named Geoffroi II De.