paid 250 marks for his release. His mother was Eleanor, daughter and coheiress of Stephen de Thurnham or Turnham, another Kentish magnate (Archæologia Cantiana, v. 152, 193; a chart facing p. 222 corrects Dugdale, Baronage, ii. 13). He could hardly have been born later than 1220. In 1251 he came into his inheritance on the death of his father. At the jousts held at Walden, Essex, in 1252, he slew Arnold de Montigny, against whom he was tilting; he professed deep sorrow, but as it was discovered that his lance's point was not covered by a socket, as it should have been, he was suspected of murderous intent, for it was remembered that he had had his leg broken by Arnold in a joust. He assumed the cross and took out a pardon from the king. In 1253 he accompanied Henry III [q. v.] to Gascony. He was intimate with the king's son Edward [see Edward I], accompanied him to many jousts in England and France, was his steward, and kept his purse (Gervase, Gesta Regum Continuata, ii. 220). While serving against Llewelyn of Wales in 1256 he narrowly escaped being slain. In 1258 he sided with the baronial party, swore to the Provisions of Oxford, and was with his associates included by name in the papal bull of excommunication. Acting as Edward's steward in 1260 he hanged some of the servants of the Earl of Gloucester [see Clare, Richard de, eighth Earl of Clare, &c.] in the Welsh marches, unjustly it was said, and without trial, whereupon the earl quarrelled with Edward (Chronicles of Edward I, i. 54). In the same year he accompanied Edward to France, and at Paris received from him a grant of the manor of Elham, Kent. Soon afterwards the queen [see Eleanor of Provence], angered by Leybourne's association with the baronial party, stirred up Edward against him. An account of his stewardship was demanded, and he was declared by the exchequer to be 1,000l. in arrears, though the accusation is said to have been false. Process was issued, and as he removed all his goods from his manors to avoid distraint, writs were sent out to inquire after and seize them in Kent, Essex, and Sussex. At the same time the king demanded from him the manor of Elham, on the plea that it was inalienable from the crown (Gervase, u.s.; documents cited in Archæologia Cantiana, v. 166–70). Being stripped of all his revenues, Leybourne took to marauding, and Sir William de Detling having been dispossessed of Detling, Kent, by his lord the Archbishop of Canterbury, for homicide, Leybourne joined him in forcibly ejecting the archbishop's officers, and put his own son in possession of the manor. He attended the meeting of the barons at Oxford at Whitsuntide 1263, and joined himself with Roger de Clifford (d. 1285?) [q. v.] and others. Associating themselves with Simon de Montfort, earl of Leicester, they seized Peter the Savoyard bishop of Hereford, took Gloucester, with the consent of the townsmen occupied Bristol, and then proceeded eastward, everywhere seizing the property of the aliens and their supporters. Leybourne marched with Earl Simon to Dover, and on 9 July to Romney. By 18 Aug., however, he and other lords, some of whom were, like himself, old servants of Edward, were won over by Edward, and executed a deed of reconciliation with him. Leybourne was at once made steward of the household to the king and queen and Edward, and on 3 Dec. was appointed warden of the Cinque ports.
As one of the king's adherents Leybourne swore to submit to the award of Louis IX of France, and in February 1264 crossed over to Witsand to bring Henry back to England. He marched with the king's army to Northampton, and was sent with Earl John de Warrenne to secure the south-eastern counties. He joined in the defence of Rochester against the baronial army, and burnt some of the buildings of the monastery and the suburbs of the city (Rishanger, De Bellis, notes p. 127). He was badly wounded during the siege (Hemingburgh, i. 313), which was raised on the approach of the royal army. He was taken prisoner at the battle of Lewes on 14 May, and was set at liberty on giving security that he would appear in parliament when summoned (Annals of Dunstable, p. 232). Joining himself to the marchers and others of the king's side he took part in the attempt to rescue Edward at Wallingford and in the war carried on in the marches of Wales and the western districts. When summoned to appear at Windsor before the king's council he and his allies refused to obey, and sentence of banishment for a year and a day was pronounced against them. In December they came to terms with the government, and Leybourne and Clifford met the king at Pershore, and were allowed to visit Edward at Kenilworth (Fœdera, i. 449). They promised to retire to Ireland, but soon took up arms again, and caused the Earl of Leicester much trouble. On 23 May 1265 Leybourne and Clifford received a safe-conduct to visit Edward at Hereford, and there, no doubt, arranged with him for his escape, which he effected on the 28th. Leybourne joined Edward and took part in the battle of Evesham on 4 Aug. In September he was sent by the king to London, held an assembly of the citizens in
