The son of this marriage [William & Aubrey], William FitzWilliam (the alleged Marshal of Hastings [which he was not]) was probably just of age in 1194, when, by a fine dated 21 Apr, Roger the Constable, Aubrey's grandson by her first husband, released to her and her son William (FitzWilliam) all the lands which had belonged to Robert de Lisours her father. The subsequent pedigree can be sketched very briefly. Aubrey's son William FitzWilliam, was living 9 Feb 1218/9. [Complete Peerage V:518-519 Note]
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This feudal lord took up arms in the baronial cause, temp. King John, but returned to his allegiance in the 5th Henry III [1221]. He m. Ella, dau. of Hamlyn, Earl Warren and Surrey, and was s. by his son, Sir Thomas Fitz-William. [Sir Bernard Burke, Dormant, Abeyant, Forfeited and Extinct Peerages, Burke's Peerage, Ltd., London, 1883, p. 215, Fitz-William, Baron Fitz-William]