The castle of Dunbar was at this time one of the strongest, and, by its situation, most important in Scotland. Its lord, Patrick earl of Dunbar, served in the army of Edward; but his wife, the countess, who held the castle, and hated the English, entered into a secret negotiation with the Scottish leaders, for its delivery into the hands of her countrymen. The Earls of Ross, Athole, and Menteith, the barons John Comyn, William St Clair, Richard Seward, and John de Mowbray, with thirty-one knights, and a strong force, threw themselves into the place; and, assisted by the countess, easily expelled the few soldiers who remained faithful to England.
On being informed of this loss, Edward determined upon recovering it at all hazards; and for this purpose despatched the Earl of Surrey with ten thousand foot', and a thousand heavy-armed horse. When summoned by Warrene, the garrison agreed to surrender, unless relieved within three days; and the Scots, anxious to retain so important a place, led on the whole of their army, and possessed themselves of a strong and excellent position on the high ground above Dunbar. Forty thousand foot, and fifteen hundred horse, encamped on the heights, near Spot; and, confident of rescue, the garrison of the castle insulted the English from the walls, as if already beaten.