WILLIAM DE MUNCHENSY, brother and heir, received possession of Gooderstone in December 1179; was knighted before 1185, and had succeeded his brother by Michaelmas 1190. He had done military service in person before Michaelmas 1194 and in 1198 was serving in Normandy. In August 1199 at Roche d'Andelys he was one of the guarantors of the treaty between King John and the Count of Flanders. He was one of those who fined for not serving overseas in 1201; and was a benefactor of the houses of West Dereham and Missenden.
He married, before 1186, Aveline, daughter of Roger (DE CLARE), EARL OF HERTFOAD, by Maud, daughter and heir of James DE ST. HILAIRE, of Dalling, &c., Norfolk, &c. He died before 7 May 1204. His widow married, before 29 May 1205, Geoffrey (FITZ PIERS), EARL OF Essex. She died before 4 June 1225. [Complete Peerage IX:420, (transcribed by Dave Utzinger)]