Situated three and a half miles north by east of Newcastle, County Down, this donjon fortress commands an extensive view of Dundrum Bay and the surrounding district of Lecale. The castle was built on the site of an older fortification known as Dun Rudhraidhe, or Rury’s Fort, which is said to have been the scene of the great feast given by Bricrin of the Poisoned Tongue, to King Connor MacNessa and the Red Branch Knights at which he induced them to make war on one another, as is chronicled in “The Book of the Dun Cow.” The present village of Dundrum (Dundroma, signifying the fort on the ridge) lies between the castle and the shore, while to the east of the fortress are the ruins of an Elizabethan mansion erected by a former owner of the castle.
The circular keep or donjon is built upon a rock, and has an external diameter of some 45 feet, the walls of which are 8 feet thick above the projecting base. The tower at present stands about 50 feet in height. The cellar below is hewn out of the rock on which the building was erected, and is said at one time to have contained 200 tuns of Spanish wine belonging to O’Neill.
To the east of the entrance is a circular newel stair 3 feet 3 inches in diameter, constructed in the thickness of the wall and leading to the parapet. From this there are openings at each storey, and it is most likely from the position of the offsets in the wall that the floors were of wood supported on beams, the holes for the latter being still visible at different levels.
Round this tower was the courtyard or bawn, encircled by a high wall 4 and 5 feet thick, which was again protected by a fosse or moat, still to be seen on the north and west sides. The bawn was occupied by the buildings for the retainers, and perhaps the family in times of peace, and is of a roughly circular form about 150 feet across.
DUNDRUM CASTLE, CO. DOWN.
South-east of the donjon, in the line of wall, are the two ruined towers which protected the barbican gate, the corbel blocks of which still remain over the archway, and originally supported the defences of the gateway. From these, numerous rebels were hanged in the rebellion of 1798.
The castle was built of stone quarried to form the fosse, mixed with land stones of the district. Little has been done to alter the twelfth or thirteenth century architecture, except the opening out of windows. On the side of the ruined manor the outer fortifications would seem to have been levelled to make terraced gardens to the later dwelling.
It is generally supposed that Dundrum Castle was built by John de Courcy at the end of the twelfth century for the Knights Templars, after his daring conquest of Ulster in 1177 with only a force of about a thousand men. The stronghold remained in the possession of the order (which was bound by vows of chastity, poverty, and obedience) until the suppression of the Knights Templars in 1313. It then passed into the hands of the Prior of Down, and is mentioned by Archdall in his “Monasticon Hibernicum” as a religious house. Upon the abolition of the monasteries the reversion of the castle and manor, with a yearly rent of £6 13s. 4d. reserved out of it, was granted to Gerald, Earl of Kildare.