William's alien origin and rich marriage involved him in an unpopularity which was soon intensified by his pride and violence. Henry dubbed him knight on 13 Oct. 1247 in Westminster Abbey (Matt. Paris, iv. 640–4). Though still ‘ætate tener et viribus imperfectus,’ his eagerness to win distinction in tournaments led him to break the king's orders by striving to hold a joust about Northampton (ib. iv. 649, cf. v. 54). He was ‘egregie bajulatus’ on 4 March 1248 at a tournament at Newbury (ib. v. 17, 18), but won a signal triumph in 1249 at Brackley (ib. v. 83). He was always much attached to such encounters, and ransacked the continent to procure choice horses (Deputy Keeper of Publ. Rec. 46th Rep. p. 308). On 2 Oct. 1249 he was appointed joint ambassador to France (Fœdera, i. 270). His father having died on crusade, he took the cross on 6 March 1250 (Matt. Paris, v. 101). This gave the king three years later an excuse for advancing to him 2,200 marks from the crusading funds (Rôles Gascons, i. 388).
In 1253 William accompanied Richard de Clare, seventh earl of Gloucester [q. v.], to France on the occasion of Gilbert of Clare's marriage to William's niece Alice of Lusignan. He was defeated in a tournament, and ridiculed by the French for his effeminacy, if a hostile witness can be trusted (ib. v. 367). In November 1253 and September 1254 he was in Aquitaine with Henry III, where his expenses gave excuse for fresh grants in his favour (Rôles Gascons, i. 242, 314, 413, 465).
In 1255, on the death of his father-in-law, Warin de Munchensi, the king gave Valence the custody of the heir, his wife's half-brother, William de Munchensi (d. 1289) [q. v.] Strange tales are told by Matthew Paris of his boastfulness, pride, and violence. Hertford and its neighbourhood were especially exposed to his outrages (Matt. Paris, v. 343–4). He bore special ill will to the monks of St. Albans (ib. v. 229). His deeds were not only unlawful but unknightly. He advised Henry to undertake his rashest measures, such as the acceptance of the Sicilian crown for his son Edmund. His close association with the Lord Edward was regarded as an evil omen (ib. v. 679). He joined his brother Aymer in his quarrel with Archbishop Boniface and the Savoyards, for which he incurred excommunication. But this, though it made him odious to Queen Eleanor, did not destroy his influence at court.
Conflicting interests in West Wales brought William into violent opposition to Simon de Montfort [q. v.] In 1257 his steward raided Leicester's lands (ib. v. 634). As Simon became hostile to the crown their enmity became more intense. In the London parliament of April 1258 he called Simon an ‘old traitor,’ and a personal encounter was with difficulty prevented. Meanwhile grants were still lavished upon him. Naturally no cry was more general among the barons than for the expulsion of the Poitevins, and William was looked upon as the chief of the gang. How much confidence Henry placed in them is shown by William and two of his brothers being put with his brother-in-law Warenne among the twelve nominees of the king included in the reforming committee of twenty-four appointed by the Mad parliament. All four refused to swear to observe the provisions of Oxford, and after fresh altercations between William and Simon, the Poitevins fled from Oxford. Unable to reach the coast, they threw themselves into Aymer's castle of Wolvesey at Winchester, whither they were pursued by the barons. Abandoned by Warenne, William and his brothers were forced to negotiate with the besiegers. Not illiberal terms were offered them, and they agreed to withdraw from the realm and abandon their castles if they were allowed to remain possessed of their lands, and to take six thousand marks of their treasure away with them. William's share of this was three thousand marks. On 5 July they received safe-conducts and went to Dover by way of London. Either there or at Winchester they were suspected of attempting to poison some of the nobles at a banquet (Matt. Paris, v. 702). Their baggage was searched by the castellan of Dover, who confiscated their valuables, while other sums found at the Temple and in other houses of religion were also seized (ib. v. 704). If Matthew Paris's account be literally true, it suggests that the barons were not very scrupulous in respecting the conditions arranged at Winchester. On 14 July William and his brothers crossed the Channel. Henry de Montfort followed them, and, raising troops, kept them for some time in a state of quasi-siege at Boulogne. Their plight was the worse since Queen Margaret of France resented their hostility to her sister and her uncles (ib. v. 703). At last, however, Louis IX extended his protection to them, and, releasing them from Boulogne, allowed them to cross France to Poitou (ib. v. 710). In England their enemies deprived William's wife Joan of part of her estates, allowing her only such of her own inheritance as she had possessed before her marriage, lest she should send supplies to her exiled husband (ib. v. 721); she left England in Advent and joined her husband (ib. v. 672).
William's exile from his adopted country
