Initially called the Earl of Kildare, the family, called the Fitzgeralds, came to Ireland with the Normans in the eleventh century, becoming as was said more Irish than the Irish themselves, a phrase with noted how various new waves of arrivals in Ireland adapted Irish culture, religious practices and the language of the native Irish, becoming exactly what the phrase implies. Two senior Fitzgeralds, Garret Mór Fitzgerald and his son, Garret Óg Fitzgerald served as Lords Deputy of Ireland (the representative of the King of England in Ireland).
The subsidiary titles of the Duke of Leinster are: Marquess of Kildare (1761), Earl of Kildare (1316), Earl of Offaly (1747), Viscount Leinster (1747), Baron Offaly (1620) and Baron Kildare (1870). The Viscounty of Leinster is in the Peerage of Great Britain, the Barony of Offaly in the Peerage of the United Kingdom, and all other titles in the Peerage of Ireland. The courtesy title of the eldest son and heir of the Duke of Leinster is Marquess of Kildare.
The family was originally based in a large castle in Maynooth in County Kildare. In later centuries the family owned estates in Waterford with country residence being a georgian house called Carton House which had replaced the castle in County Kildare. In Dublin, the Earl built a large townhouse residence on the southside of Dublin called Kildare House. When the Earl was awarded a dukedom and became Duke of Leinster, the house was renamed Leinster House. One of its occupants was Lord Edward Fitzgerald, who became an icon for Irish nationalism through his involvement with the nationalist rebellion of 1798, which ultimately cost him his life. Leinster House was sold by the Leinsters in the early nineteenth century. After nearly a century as the headquarters of the Royal Dublin Society, which held its famed '"Spring Show and Horse Show in its grounds. In 1922, Oireachtas Éireann'', the two chamber parliament of the new Irish Free State, rented Leinster House to be its temporary parliament house. In 1924 it bought the building for parliamentary use. It has remained the parliament house of the Irish Free State (now called the Republic of Ireland).
The Dukes of Leinster in by the early 20th century had lost all their property and wealth. Their Carton House seat was sold (through one of Ireland's most historic buildings with perfectly preserved 18th century grounds, it was controversially turned into a hotel and golf course in the late 1990s by the current owner in an act condemned by environmentalists), as later on was their other residence in Waterford. The current Duke of Leinster works and lives in the United Kingdom.
Dukes of Leinster