James FitzGerald, 20th Earl of Kildare (1722-1773) was created 1st Duke of Leinster in 1766. He was the son of Robert, Earl of Kildare (1675-1744) and his wife Mary, eldest daughter of William O'Brien, 3rd Earl of Inchiquin. He was born on 29 May 1722, and styled Lord Offaly until 1744, when he succeeded his father to the peerage as Earl of Kildare. He accepted a post in the Government as Lord Deputy in 1756, and that of Master General of the Ordinance in 1758, and in 1761 was created Marquess of Offaly in the peerage of Ireland. Five years later he was created Duke of Leinster in the peerage of Ireland at a time when there were no other Irish Dukes. While his principal seat was the Palladian Carton House, in county Kildare, which had been built by his father and where, together with his wife, he created one of the most idyllic landscape gardens in Ireland, he also built, between 1745-48, Kildare House in the south of Dublin which would be later become home to the parliament of Ireland.

Carton House, Maynooth, Co. Kildare the ancestorial home of the FitzGerald family, Earls of Kildare and Dukes of Leinster, who had been connected with the lands there since the 12th century. Located fourteen miles west of Dublin, the house as it stands today was is the result of the 19th Earl of Kildare's vision, employing the celebrated architect Richard Cassels to create one of the most celebrated neoclassical mansions in Ireland. The house was further remodelled in the early 19th Century by the 3rd Duke of Leinster, who added a huge barrel-vaulted dining room and colonnaded links to the wings on either side of the main house. The house remained in the FitzGerald family until being sold by Edward FitzGerald, 7th Duke of Leinster (1892-1976) following the Second World War, bringing to a close seven centuries of family stewardship.

See also lot 1.