Bruce, like all his family, had a complete belief in his right to the throne. His ambition was further thwarted by John Comyn, who supported John Balliol. Comyn was the most powerful noble in Scotland and was related to many other powerful nobles both within Scotland and England, including relatives that held the earldoms of Buchan, Mar, Ross, Fife, Angus, Dunbar, and Strathearn; the Lordships of Kilbride, Kirkintilloch, Lenzie, Bedrule, and Scraesburgh; and sheriffdoms in Banff, Dingwall, Wigtown, and Aberdeen. He also had a powerful claim to the Scottish throne through his descent from Donald III on his father's side and David I on his mother's side. Comyn was the nephew of John Balliol.