William de Mowbray
In 1194, on coming of age, William took livery of his lands on payment of the usual £100 "relief". He was immediately called upon to pay a similar sum in tax for the ransom of King Richard I . In 1197 he was one of the witnesses to the English treaty with Flanders.
In 1199 Richard I died and whilst King John delayed his claim to the throne William was amongst the powerful group of barons who seized the opportunity to fortify their castles. However, like the rest he was induced to swear allegiance by the promises which Archbishop Hubert Walter, the justiciar Geoffrey Fitz-Peter and William Marshall made in his name, but the king appeared to think it prudent to exempt him from the tax raised early in 1200.
William de Stuteville renewed an old family claim to lands which had come to the Mowbrays from the Frontebouefs, even though his father had made a compromise with William de Mowbray's father, Nigel. The latter William supported his claim by a present of three thousand marks to King John, who, with his great council, dictated a new compromise. By this, Stuteville had to accept nine knights fees plus £12 in full satisfaction of his claim. The two Williams were reconciled on 21 Jan 1201 at Louth in the country house of the Bishop of Lincoln.
In 1215 William was prominent in the baronial war against King John. From this date there is a physical description by a contemporary as "short as a dwarf". His difficulties of getting on a horse fully armoured were pushed aside and by his own efforts he was man to be reckoned with. He was one of the principals pressing for the creation of the Magna Carta being in the list of 25 barons at the signing at Runnymede. As one of those appointed as executor he was named amongst those excommunicated by the Pope.
In 1217 he was again in conflict with the monarch, now Henry III, and on being taken prisoner at the Battle of Lincoln, his lands were bestowed on William Marshall. By surrendering his lordship of Bensted in Surrey to Hubert de Burgh, he redeemed his former lands. Thereafter he seems to have supported the king again, for in January 1221 he was with the royal army at the siege of Bytham Castle, Lincolnshire. This assisted Hubert de Burgh in driving out William of Aumale, another Magna Carta colleague, form his last stronghold.
In 1222 William died at Axholme, Lincolnshire, the Mowbray caput baronae