But again in 1565 it was occupied by the great Shane O’Neill, who placed his own ward in it for defence, and the Magennises (with whom O’Neill was intimately connected) were in possession of the stronghold in 1601, when Phelim Magennis surrendered it to Lord Mountjoy.
O’Neill is said to have been a constant visitor at the castle while it was possessed by the Magennises, Lords of Iveagh, and after a night of revelry would indulge in a strange kind of bath, by being buried to his neck in the sands on the shore of the bay.
Four years subsequently to the stronghold passing into the hands of the Crown, Lord Cromwell was commissioned to be governor and commander of Lecale and the tower and castle of Dundrum.
In 1636, Lord Cromwell’s grandson, Thomas, Lord Lecale and 1st Earl of Ardglass, sold it to Sir Francis Blundell, from whom it descended by marriage to its present owner, the Marquis of Downshire.
Sir James Montgomery fought the Irish on the shore at the foot of the castle hill 1642, and placed a garrison in the fortress to protect the district. At this time Dundrum belonged to the Blundells, who afterwards built the now ruined mansion adjoining, and the ancient stronghold was finally dismantled in 1652 by the order of Oliver Cromwell.
Phillips, “Dundrum Castle.” Praeger, “Guide to County Down.” Joyce, “Irish Names of Places.” Grose, “Antiquities of Ireland.” Harris, “History of County Down.” Calendar of State Papers. “Notes to Sir Henry Sidney’s Memoir,” and “Facsimiles of Signatures of Irish Chieftains” in _Ulster Journal of Archæology_.
This fortress was one of the long chain of the Pale castles which defended the metropolis, but having been inhabited until the beginning of the nineteenth century it is in a much better state of preservation than most of these old buildings.
It is situated about three miles south of Dublin on a rise of ground above the Dundrum River, a tributary of the Dodder, at the junction of the Ballinteer and Enniskerry roads.
It is probable that the castle was built on the site of a more ancient stronghold, as Dundrum signifies “the fort on the ridge.”
The principal ruin of the present castle is a keep which is battlemented in a slightly projecting form on the south-east, while the south-west wall rises in rather a high gable. The building is oblong in shape, and the entrance, which is on the south side, is evidently of more modern construction. A gate now gives egress to the interior, which is occupied by a flower bed.