of certain liberties for pilgrims going to Compostella. In September 1255, Mansel and Richard de Clare, earl of Gloucester, were sent to Edinburgh to inquire into the treatment of the young queen Margaret. This delicate mission was successfully performed, and Margaret and her husband were released from the tutelage of Robert de Ros and John de Baliol (Cat. Docs. Scotl, i. 381-8). As a consequence of his negotiations with the pope, Henry III had agreed to go to Apulia and prosecute his son Edmund's claims in person. For this purpose he desired a free passage through France, and on 24 Jan. 1256 Mansel was sent to treat with Louis IX (Fœdera, i. 335). On 30 Jan. Henry wrote a long letter to Mansel with reference to the affairs of Gascony and Castile, giving him full authority to decide the matter on account of his great knowledge of the subject (Shirley, ii. 110-11). In June Mansel was sent with the Earl of Gloucester to Germany, to negotiate with the electors as to the choice of Richard of Cornwall to be king of the Romans. After much bargaining and bribery their object was accomplished by the election of Richard on 13 Jan. 1257 (Ann. Mon. iv. 112). Mansel was back in England in time for the Lent parliament on 25 March. In June he was appointed, with Simon de Montfort and others, to treat with the pope as to Sicily, but does not appear to have left England (Fœdera, i. 359-60). During the summer both of this and the following year he was engaged in the north of England and in Scotland on missions to arrange the dispute between Alexander III and his rebellious subject' (ib. i. 347, 376; Cal. Docs. Scotl. i. 2131, 2133; Chron. de Mailros, p. 184). In January 1258 he held an examination of the civic officers of London at the Guildhall, and deposed several aldermen (Lib. de Ant. Legibus, pp. 30-7, Camden Soc.; Ann. Lond. in Chron. Edw. I and II, i. 50).
When at the parliament of Oxford in June 1258 Henry had to assent to a new scheme of government, 'the provisions of Oxford,' Mansel was named one of the royal representatives on the committee of twenty-four, and was likewise a member of the council of fifteen, having previously been one of the two royal electors appointed for its choice. In March he was associated with the Earls of Leicester and Gloucester and others in the mission to France, which led to the abandonment of the English king's claims on Normandy. In May he was employed with the Earl of Gloucester to arrange the marriage between Henry's daughter Beatrice and John of Brittany (Fœdera, i. 382, 386). In October he was with the queen at St. Albans, and in the following month accompanied the king to France (cf. Shirley, ii. 152, 155). When Edward quarrelled with his father in 1260, Mansel and Richard, earl of Gloucester, were the only royal counsellors who were admitted freely to the kind's presence. In August 1260 the temporalities of Durham were entrusted to Mansel during the vacancy of the see, and while in charge of the bishopric he entertained the king and queen of Scotland in October (Flores Hist. ii. 455; Cal. Docs. Scotl. i. 2204).
Mansel is said to have advised Henry to withdraw from 'the provisions' (Ann. Mon. iv. 128), and in March 1261 Henry was compelled to dismiss him from his council. Mansel took refuge in the Tower, but when in May he learnt of the removal of the baronial justiciar and chancellor by the king, he left London by stealth and joined Henry at Winchester. Mansel was apparently alarmed for the consequences of Henry's action, and by his advice the king then came to London; no doubt he was Henry's adviser in his subsequent vigorous action with regard to the appointment of the sheriffs.
On 5 July he was one of the arbitrators to decide all grounds of dispute between the king and the Earl and Countess of Leicester (Shirley, ii. 175). In November he was one of the arbitrators appointed to decide the dispute as to the appointment of the sheriffs (Ann. Mon. iv. 129). On 1 Jan. 1262 the council charged Mansel with having stirred up strife between the king and his nobles, but Henry on the same day addressed a warm letter of defence to the Roman curia (Fœdera, i. 414). It was through Mansel's exertions that in the following month a papal bull was obtained, securing for Henry the fullest release from all his obligations (Shirley, ii. 206). In July he went over with the king to France as keeper of the great seal, but resigned the office on 10 Oct., and after that date is again called the king's secretary. He returned to England with the king on 20 Dec. When open war broke out in the following spring, Mansel was one of the chief objects of the barons' wrath. After sheltering for some time in the Tower, he proceeded stealthily with the king's son Edmund to Dover, and thence on 29 June crossed over to Boulogne, Henry of Almaine, then a supporter of De Montfort, pursuing him in hot haste. All his lands in England were bestowed on De Montfort's son Simon. Mansel never returned to England; he was present at the Mise of Amiens on 23 Jan. 1264, and in February was acting for Henry in his negotiations with Louis IX. After the battle of Lewes he was one of the royalists who