Dundrum, or the Magennis Castle, as it may have looked in earlier times.
This 12th-century castle with its circular four-storey high keep was built by the Anglo-Norman knight John deCourcy on the summit and slopes of a 200-foot-high hill, and was the object of frequent struggles between the invaders and the native Irish.The castle was besieged and taken over in 1210 by king John, and it remained in royal possession until 1227, when Henry III made it over to Hugh deLacy the Younger.
The castle occupies a magnificent location, dominating the surrounding countryside and the sea. It is built on a prominent hill of shale and grit, carved out by the ice during the last Ice Age. Bare rock is clearly visible, especially under the gatehouse and in the defensive ditch which surrounds the castle. Situated on the western shore of Dundrum Inner Bay, it commands a fine natural harbour which offered easy penetration inland, especially to the fertile Lecayle peninsula. This strategic importance, recognised by the builders of the early Christian “dún” or fort, which previously occupied the site, and those of the Anglo-Norman castle, was described by Lord Leonard Grey, who took Dundrum in 1538 as: “one of the strongest holds in all of Ireland, and most commodious for defence of the whole countrie of Lecayle both by sea and land, for Lecayle is environed by the sea, and there is no way to enter it by land but by the said castle”. Although one of the delights of the hill is now its tree cover, the surroundings of the castle must have been far more open at the time it was in use, since trees would have provided unwelcome cover for assailants.
via Dundrum Castle