Sir William de Ferrers died circa 20 December 1287.
In 1251 his father gave him the manor and advowson of Woodham, the manor of Stebbing, the capital messuage at Chiche (now St. Osyth), and lands in Fairsteed, Essex, to hold in tail general, by the service of five knights' fees. Between 4 and 5 years later, before he was of age, he had livery of these lands; subsequently he exchanged them with his mother for lands in Scotland and Galloway, but he again had entry therein, with her consent, 16 days before her death in Feb. 1280/1.
He was summoned for military service from 18 Marsh 1263/4 to 14 March 1282/3.
He was among the prisoners taken after the conflict at Northampton 5 or 6 April 1264, and was committed by Edward the king's son to the custody of Roger de Leybourne. Roger demanded an excessive ransom, threatening to take him to Ireland if he did not pay it; on 5 Jan. 1264/5 Roger was ordered to release him and let him come to the king. Wiliam was admitted to the king's presence and pardoned all trespasses committed by him up to 11 July 1266. 
At an unknown date he gave to Charley Priory 5-1/2 acres near their sheepfold for the purpose of enlarging the courtyard of the priory; sometime before 1272, he likewise gave the same priory 30 acres of land in the Milne-leghs by Charley, Leicestershire.
↑ 1.01.1 Douglas Richardson, Magna Carta Ancestry, 2nd Edition, Vol. II, p. 150-152.
↑ 2.02.1 Douglas Richardson, Royal Ancestry, Vol. II, p. 561-562.
↑ 3.03.1 Douglas Richardson, Royal Ancestry, Vol. III, p. 145.
↑ Douglas Richardson, Magna Carta Ancestry, 2nd Edition, Vol. II, p. 290.
↑ 5.05.15.25.35.4 Douglas Richardson, Magna Carta Ancestry, 2nd Edition, Vol. II, p. 290-292.
↑ 6.06.1 Douglas Richardson, Royal Ancestry, Vol. III, p. 145-147.
↑ 7.07.1 Douglas Richardson, Magna Carta Ancestry, 2nd Edition, Vol. II, p. 152.
↑ 8.08.1 Douglas Richardson, Royal Ancestry, Vol. II, p. 564.
↑ Douglas Richardson, Royal Ancestry, Vol. IV, p. 590.
↑ 10.010.110.2 Douglas Richardson, Royal Ancestry, Vol. III, p. 149.
↑ The Complete Peerage of England, Scotland, Ireland, Great Britain, and the United Kingdom, by George Edward Cokayne, Vol. V, p. 341.
↑ 12.012.112.212.3 Richardson, D. Magna Carta Ancestry: A Study in Colonial and Medieval Families, Royal Ancestry series, 2nd edition, 4 vols., ed. Kimball G. Everingham, (Salt Lake City, Utah: the author, 2011), Volume I, page 290, #4. Google eBook
Magna Carta Ancestry 2011 2d ed. Vol. II p. 290-295.
Richardson's Magna Carta Ancestry lists only William as a child. Ann and Julian are children of Ann Despenser, not a wife of this William. Please see the discussion in this profile from Douglas Richardson.