The castle is pleasantly situated on rising ground between hills. It is usually supposed to have been erected by the Lords Courcey, who received a grant of the lands shortly after the Anglo-Norman landing, but in 1743 Robert Clayton, Bishop of Cork, sent copies of two inscribed stones, found at Kilbrittain, to John, Earl of Egmont. These stones bore the date 1035 in the Arabian characters, which seems to indicate an earlier date of erection. He says: “The stone from which the inscription was taken was found by Mr. Stawell in an old castle, which he has since pulled down, called Kilbrittain, which signifies in Irish the ‘church or cell,’ or rather the ‘burial place of the Britains.’ Mr. Stawell says there was likewise the figure of a woman carved in _bas-relief_ on another stone, the workmanship of which being most curious. He neglected it, and it has since been lost.” The manor of Kilbrittain passed into the King’s hands in 1295 upon the death of John de Courcey, who was slain on the Island of Inchydonny by M’Carthy. Walter de la Haye, the King’s escheator, delivered the lands to James Keating in keeping for De Courcey’s heir. Lord Courcey, it is said, borrowed a white weasel or ferret from M’Carthy, and pledged his castle as surety for its safe return, but the animal dying M’Carthy claimed Kilbrittain, and it thus passed out of De Courcey’s hands. In 1430 M’Carthy Reagh and James, Earl of Desmond, “The Usurper,” began hostilities, and the castle was stormed by the Earl and given to his brother Donough, who had assisted at its capture, but it subsequently returned to the M’Carthys. In 1537 Lady Eleanor M’Carthy resided in the castle after her husband’s death. She was sister to Gerald, 9th Earl of Kildare, and, therefore, aunt to Thomas, the “Silken Lord,” and his half brothers. After Lord Offaly’s rebellion, and execution, and the attainting of the house of Kildare, the young heir Gerald escaped from the Government by the aid of his tutor Thomas Leverous, afterwards Bishop of Kildare, who wrapped him in a blanket, and fled with him although the lad was sick with smallpox. After a hot pursuit they reached Kilbrittain where the Lady Eleanor took charge of her nephew. She subsequently married O’Donnell of Ulster to gain protection for the boy, but finding her husband was treating with the Government to betray him, she sent the future Earl to France and returned to her son’s territory in the County Cork. In 1572 Kilbrittain is spoken of as M’Carthy Reagh’s chief dwelling-place, and it is mentioned that he paid a yearly rent of 67 beefs for it to the Earl of Desmond, besides rendering him military service at times. Eighteen plough lands are mentioned as attached to it in 1599.