He thus inherited a dispute with the Prior of Gisborough, concerning the appointment of the parish priest at Kirkleatham, particularly that the Prior had tried to gain control of the parish whilst Sir William was infirm. When Robert had exhausted all the ecclesiastical routes of appeal, he turned to rebellion (around Easter 1232), and raided church properties, especially those belonging to foreign churchmen, under the sobriquet Will Wither ( literally ‘William the Angry’), and he distributed the spoils to the poor. He was excommunicated by the Papal Legate in England, Cardinal Otto.
He was given support by the great northern Magnate families: Percy, Nevill, Fitz-Randolph, de Vesci, de Maulay, de Menyll, de Roos and de Brus.
He presented his case to Henry III of England who, rather than punish him, gave him letters of recommendation to take to take to Pope Gregory IX, the latter of whom ruled in his favour, bringing the rebellion of Will Wither to an education Biographies suggest that the influence of Richard of Cornwall may have been decisive in this case.
In 1240 Robert set out with Richard on Crusade, however, he probably never reached The Holy Land, as he was despatched as an envoy to Frederick World War II In 1244 he was charged with assaulting the Archbishop of York, Walter de Gray, and his lands were seized, but later returned to him.