In the year 1333, King Edward III., espousing the cause of Edward Baliol, invaded Scotland. The battle of Hallidon Hill, July 29th, in which the Regent Douglas was defeated, placed Baliol on the throne; and Edward, carried away by his ambitious designs upon the French throne, left his army in charge of the Earls of Arundel and Salisbury, and returned to England. Montague, Earl of Salisbury, laid siege to the castle of Dunbar, a place of great importance, esteemed as the key of Scotland, on the south-east border. It had been fortified very recently; and in the absence of the Earl of March, was defended by the countess, who, from the dark colour of her complexion, was popularly styled "Black Agnes." She was the daughter of Randolph, Earl of Moray, and inherited from her father a fierce, intrepid spirit. During the five months' siege she performed all the duties of a bold and skilful commander, and the garrison had the utmost confidence in her abilities. Constantly on the ramparts, she derided the English with biting sarcasms. When the battering-engines hurled stones against the walls, she scornfully told one of her female attendants to wipe off the dust with her handkerchief. The Earl of Salisbury knew well the kind of foe he had to deal with. One day he was superintending the siege operations, when an arrow from the castle whizzed past and struck a knight who stood by, piercing through his chain-mail haubergeon, and killing him on the spot. "There comes one of my lady's tire-pins," exclaimed the Earl. "Agnes's love-shafts go straight to the heart!" A monster called the "sow," a huge engine covered with hides, somewhat resembling the testudo of the Romans, was at last rolled to the foot of the walls. When the countess saw this ponderous machine coming, she cried in a loud, mocking voice:-- "Montague, beware! your sow shall soon cast her pigs!" She quickly verified her words by hurling an immense piece of rock upon the "sow," crushing both it and its occupants to pieces. Salisbury finding he could not succeed by fair means, bribed the gate-keeper to leave the gates open on the following night. The porter disclosed this to the countess, who directed him to keep to his bargain and say nothing about it. The Earl, who commanded the party that were to seize the castle, rode through the darkness at the head of his soldiers, found the gates open according to agreement, and was about to enter, when one of his men, John Copeland, passed in front of him. The portcullis was suddenly dropped; Copeland, mistaken for his master, remained a prisoner. The Earl was saved by his men, who dragged him back just in time. Agnes, from a high turret, saw that the general had escaped. "Farewell, Montague!" she cried. "I intended that you should have supped with us to-night, and assisted in defending the fortress against the English."