The mansion has an imposing frontage, flanked at both sides by circular towers. One of these dates from the castle’s erection, and the other, which is a copy, from the year 1666. The centre block of masonry was entirely restored in the middle of the nineteenth century. Some of the walls, which were removed at that time, were 15 feet thick, being composed of rubble and excellent mortar. The old carved stone over the door was copied in Caen stone. The Royal Arms are surmounted by a figure of Charles I., while below are the family arms. The original stone, which was much weather worn, has been placed over a small door at the side. Most of the stone used at the restoration was quarried on the estate, but the facing stones were brought from Scotland. One of the special attractions of this charming residence is the beautiful terraced gardens lying to the south. They consist of three tiers of cultivation beginning with the “Box Garden” of trim flower-beds, from which you descend by a flight of rustic steps to “the Rockery Garden” abounding in Alpine plants. Here some beautiful and extremely ancient yew-trees are to be seen, their branches being 120 feet in circumference, while below a small lake in the centre of rose-beds leaves nothing to be desired in its delightful effect. The castle was erected by Sir John de Courcy shortly after his conquest of Ulster, and in 1356 Edward III. appointed John de Mandeville warden. After this it fell into the hands of the O’Neills, who retained it up to 1561, when Queen Elizabeth granted the territory to Hugo White. He rebuilt the castle and removed the ward from Dufferin Castle near, to garrison it. After this it was known as “White’s Castle” for many years. In 1567 the fortress was gallantly defended against a fierce attack made by the great Shane O’Neill, and he was successfully repulsed. The strength of the White family gradually decreased, and in 1590 they could only muster a hundred and twenty foot soldiers and twenty horsemen to defend their lands, while eight years later twenty footmen was the total of their fighting strength. The M’Artans and O’Neills joined together and dispossessed them, the former family taking possession of Killyleagh. Their estates were, however, forfeited at the close of the sixteenth century for the part they took in the rebellion of the Northern Earls, and some time after this the lands were granted to the Hamiltons. General Monk partly demolished the castle in 1649, and the Hamiltons began to rebuild it in 1666. James I. had created the head of the family Earl of Clanbrassil and Viscount Clandeboye, but the last to hold the title died in 1676. It is said he was poisoned by his wife, Lady Alice of Clanbrassil, a daughter of the Earl of Drogheda, who was a beautiful and vicious woman, and after plunging the estate into debt desired to contract a wealthy marriage.