William le Gros, count of Aumale and earl of York (c.11101179), magnate, was the son of Stephen, count of Aumale (d. c.1127), and Hawisa, the daughter of Ralph de Mortimer of Wigmore. William had at least two brothers and four sisters. His wife, Cecily de Rumilly, a daughter of William fitz Duncan and Alice de Rumilly, is said to have been given in marriage by Henry II. William may have had a previous wife who is stated to have left him for another earl. Cecily inherited the honours of Skipton and Copeland, and with William had a daughter, .
By 112930 William was in possession of his father's estate and may then already have begun to use the title count of Aumale. He was entrusted by King Stephen with the city of York, and was one of the leaders of the English army at the battle of the Standard on 22 August 1138. He was then an energetic young man, possessed of military ability and an outstandingly courageous spirit. He was rewarded by Stephen with the earldom of York, and thereafter was addressed in royal writs which indicate that he was Stephen's supreme administrative official in Yorkshire. Probably in 1140 he was driven out of Galclint Castle, Yorkshire, by Alan, earl of Richmond. In 1140 also he offered to secure the vacant archbishopric of York for his relative Waldef, prior of Kirkham, in return for the archiepiscopal manor of Sherburn. When Waldef refused, William supported the royal candidate, William Fitzherbert. He was later accused of commanding in the king's name the chapter of York to elect Fitzherbert in January 1141. William fought for Stephen at the battle of Lincoln on 2 February 1141, but is stated to have fled the field, leaving Stephen to be captured. After Stephen's release in November 1141 William spent Christmas with him at Canterbury. In 1142 Stephen came north to prevent a war between William and Alan, earl of Richmond. In or about 1143 William was harassed by Ranulf (II), earl of Chester, and Gilbert de Gant, and fortified the Gant priory at Bridlington. In or about 1145 William's sister Agnes married the son of William, earl of Lincoln. In 1148, after the deposition of Fitzherbert, William was excommunicated by the new archbishop of York, Henry Murdac, after Henry had been refused entry to York. Between c.1149 and c.1151 he probably supported Ranulf, earl of Chester, and William, earl of Lincoln, in a war fought against Gilbert de Gant, who had been set up by Stephen as a rival earl of Lincoln. William's castle at Bytham was captured, but he destroyed the Gant castle at Hunmanby. At some point in the 1140s he also captured Selby Castle, built by Henry de Lacy. By January 1151 William had apparently become reconciled with Henry Murdac, and in December 1153 he attested the treaty agreed between Stephen and Duke Henry.
William used his position during Stephen's reign to establish his domination over an extensive network of hundredal and soke manors in Yorkshire. William of Newburgh declared that he was more truly the king, beyond the Humber than King Stephen. In 1155, however, Henry II compelled William to submit, and to surrender the royal manors which he controlled and the castle he had constructed at Scarborough, and received back Yorkshire from William who stopped using the title of earl of York. Thereafter William appears to have been on good terms with Henry. In 1173 his castle at Aumale was besieged by forces supporting the Young King, and William, who may have wavered in his loyalty to Henry II, was captured and forced to ransom himself. In 1177 he witnessed the Spanish award at a council held in London. Towards the end of his life he administered the barony of Copeland with his wife.
William was a considerable benefactor of the church. He founded the priory (later abbey) at Thornton (1139) and the abbeys of Bytham (1147) and Meaux (1151), and co-founded North Ormsby Priory (114854). He made the house of St Martin-d'Auchy at Aumale into an abbey, and was a benefactor of the houses of St Bees, Bridlington, Nun Cotham, Pontefract, St Leonard's Hospital (York), St Nicholas (Exeter), and Whitby. William died on 20 August 1179 and was buried at Thornton Abbey. He was succeeded by his daughter Hawisa.
GEC, Peerage · P. Dalton, Conquest, anarchy, and lordship: Yorkshire, 10661154, Cambridge Studies in Medieval Life and Thought, 4th ser., 27 (1994) · B. English, The lords of Holderness, 10861260: a study in feudal society (1979) · W. Farrer and others, eds., Early Yorkshire charters, 12 vols. (191465), vols. 3, 7 · Symeon of Durham, Opera, vol. 2 · R. Hexham, De gestis regis Stephani et de bello standardi, Chronicles of the reigns of Stephen, Henry II, and Richard I, ed. R. Howlett, 3, Rolls Series, 82 (1886) · St Aelred [abbot of Rievaulx], Relatio de standardo, Chronicles of the reigns of Stephen, Henry II, and Richard I, ed. R. Howlett, 3, Rolls Series, 82 (1886) · R. Howlett, ed., Chronicles of the reigns of Stephen, Henry II, and Richard I, 1, Rolls Series, 82 (1884) · Reg. RAN, vol. 3 · The chronicle of Pierre de Langtoft, ed. T. Wright, 1, Rolls Series, 47 (1866) · Pipe rolls · Dugdale, Monasticon, new edn, 6.326 · W. Stubbs, ed., Gesta regis Henrici secundi Benedicti abbatis: the chronicle of the reigns of Henry II and Richard I, AD 11691192, 2 vols., Rolls Series, 49 (1867), 1.243
BL, Add. MS 26736
BL, Add. MS 40008
BL, Cotton MS Nero D.iii
BL, Lansdowne MS 424
BL, Add. MS 4715
Bodl. Oxf., MSS Dodsworth vii and xcv
Bodl. Oxf., MS Top. Lincs. d I
Bodl. Oxf., Rawl. MS B455