Maurice Fitzgerald built the castle in 1176 on a rocky promontory, directly south of the harbour. The region was granted to Fitzgerald after the 12C Anglo-Norman invasion. Until the 16C, Black Castle was subject to frequent attacks by local clansmen, the O'Byrnes and the O'Tooles. The ruins form a fine vantage point for views over the city and the coast of north County Wicklow.

This 80 ha demesne by the sea was acquired by the Reverend Robert Taylor, Dean of Clonfert, in 1737 . The original Georgian house was enlarged in the late 18C. The billiard room, dining room, small study and library contain mementoes and furniture belonging to the Taylor family. The kitchens, larder and scullery are in the basement. Beyond the rose gardens are the walled gardens, laid out with lawns, flowers and vegetables in geometric plots.

All that remains of the abbey are the Slype and rib-vaulted Chapter House where the 15C cloister has been reconstructed using the original elements, discovered in 1975. The abbey was founded in 1139 by Benedictines from Savigny. Explanations are given of its architecture, history and the Cistercian way of life.
With vast estates either side of the Liffey, it was closely associated with the city and used as a warehouse, strongroom and meeting place for the Council of Ireland.

In 1991 the museum was installed in the Royal Kilmainham Hospital, built between 1608 and 1684. The hospital was commissioned by the Duke of Ormond, James Butler of Kilkenny, appointed Viceroy in 1669; he was inspired by Les Invalides in Paris. The architect, William Robinson, designed four ranges of buildings laid out around a courtyard. They provided accommodation for 300 veterans, the last of whom died in 1929. At present, the Great Hall (north wing) provides a fine setting for government receptions. Note the Baroque ceiling in the chapel.