One summer night, when there was peace, a score of Puritan troopers under the pious Sir Frederick Hamilton, broke through the door of the Abbey of the White Friars which stood over the Gara Lough at Sligo. As the door fell with a crash they saw a little knot of friars, gathered about the altar, their white habits glimmering in the steady light of the holy candles. All the monks were kneeling except the abbot, who stood upon the altar steps with a great brazen crucifix in his hand. 'Shoot them!' cried Sir Frederick Hamilton, but none stirred, for all were new converts, and feared the crucifix and the holy candles. The white lights from the altar threw the shadows of the troopers up on to roof and wall. As the troopers moved about, the shadows began a fantastic dance among the corbels and the memorial tablets. For a little while all was silent, and then five troopers who were the body-guard of Sir Frederick Hamilton lifted their muskets, and shot down five of the friars. The noise and the smoke drove away the mystery of the pale altar lights, and the other troopers took courage and began to strike. In a moment the friars lay about the altar steps, their white habits stained with blood. 'Set fire to the house!' cried Sir Frederick Hamilton, and at his word one went out, and came in again carrying a heap of dry straw, and piled it against the western wall, and, having done this, fell back, for the fear of the crucifix and of the holy candles was still in his heart. Seeing this, the five troopers who were Sir Frederick Hamilton's body-guard darted forward, and taking each a holy candle set the straw in a blaze. The red tongues of fire rushed up and flickered from corbel to corbel and from tablet to tablet, and crept along the floor, setting in a blaze the seats and benches. The dance of the shadows passed away, and the dance of the fires began. The troopers fell back towards the door in the southern wall, and watched those yellow dancers springing hither and thither.
For a time the altar stood safe and apart in the midst of its white light; the eyes of the troopers turned upon it. The abbot whom they had thought dead had risen to his feet and now stood before it with the crucifix lifted in both hands high above his head. Suddenly he cried with a loud voice, 'Woe unto all who smite those who dwell within the Light of the Lord, for they shall wander among the ungovernable shadows, and follow the ungovernable fires!' And having so cried he fell on his face dead, and the brazen crucifix rolled down the steps of the altar. The smoke had now grown very thick, so that it drove the troopers out into the open air. Before them were burning houses. Behind them shone the painted windows of the Abbey filled with saints and martyrs, awakened, as from a sacred trance, into an angry and animated life. The eyes of the troopers were dazzled, and for a while could see nothing but the flaming faces of saints and martyrs. Presently, however, they saw a man covered with dust who came running towards them. 'Two messengers,' he cried, 'have been sent by the defeated Irish to raise against you the whole country about Manor Hamilton, and if you do not stop them you will be overpowered in the woods before you reach home again! They ride north-east between Ben Bulben and Cashel-na-Gael.'