The conduct of the younger Bruce, afterwards the heroic Robert the First, was at this period vacillating and inconsistent. His large possessions in Carrick and Annandale made him master of an immense tract of country, extending from the Firth of Clyde to the Solway; and the number of armed vassals which his summons could call inty the field, would have formed an invaluable accession to the insurgents. His power caused him to be narrowly watched by England; and as his inconstant character became suspected by the Wardens of the Western Marches, they summoned him to treat on the affairs of his master the king at Carlisle. Bruce, not daring to disobey, resorted thither with a numerous attendance of his friends, and was compelled to make oath on the consecrated host, and the sword of Thomas-a-Becket, that he would continue faithful to the cause of Edward.
To give a proof of his fidelity, he ravaged the estates of Sir William Douglas, then with Wallace, seized his wife and children, and carried them into Annandale. Having thus defeated suspicion, and saved his lands, he privately assembled his father's retainers; talked lightly of an extorted oath, from which the pope would absolve him; and urged them to follow him, and join the brave men who had taken arms against the English. This, however, they refused, probably because their master and overlord, the elder Bruce, was then with Edward. Robert, however, nothing moved by the disappointment, collected his own tenants, marched to join Wallace, and openly took arms against the English.
The news of this rebellion reached the King of England, as he was preparing to sail for Flanders. He at first disregarded it; and as many of the most powerful of the Scottish nobles were then either prisoners in England, or in attendance upon himself, and ready to embark for the continent, he was easily persuaded that it would be instantly put down by the authority of the governor. Anthony Beck, however, the martial Bishop of Durham, was despatched in great haste into Scotland; and Edward, finding from his account, that the revolt was of a serious nature, commanded the Earl of Surrey to call forth the military force on the north of the Trent, and, without delay, to reduce the insurgents.