Ирландияның Жоғары Ақсүйектік Лауазымы: Линстер Герцогі

Highest ranking noble title in the Peerage of Ireland
the title created in 1766 for the Earl of Kildare

Duke of Leinster ('/l//ɪ//n//s//t//ər/; Diúc Laighean) is a title in the Peerage of Ireland and the premier dukedom in that peerage. The subsidiary titles of the Duke of Leinster are: Marquess of Kildare (1761), Earl of Kildare (1316), Earl of Offaly (1761), Viscount Leinster, of Taplow in the County of Buckingham (1747), Baron of Offaly (c. 1193), Baron Offaly (1620) and Baron Kildare, of Kildare in the County of Kildare (1870). The viscounty of Leinster is in the Peerage of Great Britain, the barony of Kildare 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 Duke of Leinster is the head of the House of Kildare. The 3rd Duke of Schomberg, General and K. G. (1641–1719), was created The 1st Duke of Leinster in 1691. However, that creation became extinct upon Schomberg's death in July 1719. For the second creation, it was granted to James FitzGerald, 1st Duke of Leinster, who married to Lady Emily Lennox, the great granddaughter of King Charles II of the Royal House of Stuart. The family seat of the current Duke of Leinster is now Oakley Park, near Abingdon, Oxfordshire. He succeeded as 9th Duke of Leinster, 9th Marquess of Kildare, 28th Earl of Kildare, 9th Earl of Offaly, 9th Viscount Leinster of Taplow, 14th Baron Offaly, 6th Baron Kildare, and as the Premier Duke, Marquess and Earl in the Peerage of Ireland.

This branch of the Cambro Norman FitzGerald/FitzMaurice dynasty, which came to Ireland in 1169, were initially created Earls of Kildare. The earldom was created in 1316 for John FitzGerald. Two senior FitzGeralds, Garret Mór FitzGerald and his son, Garret Óg FitzGerald served as Lords Deputy of Ireland, the representative of the Lord of Ireland (the King of England) in Ireland. The tenth earl, Thomas FitzGerald, known as Silken Thomas, was attainted and his honours were forfeit in 1537. In 1554, Thomas's half brother and only male heir, Gerald FitzGerald, was created Earl of Kildare in the Peerage of Ireland. He was subsequently restored to the original letters patent in 1569, as 11th earl. The second (1554 created) earldom became extinct in 1599, although the original earldom survived.

The family was originally based in Maynooth Castle in Maynooth in County Kildare. In later centuries the family owned estates in Waterford with their 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 Irish Rebellion of 1798, which ultimately cost him his life. Leinster House was sold by the Leinsters in 1815. After nearly a century as the headquarters of the Royal Dublin Society, which held its famed Spring Show and Horse Show in its grounds, Oireachtas Éireann, the two chamber parliament of the new Irish Free State, rented Leinster House in 1922 to be its temporary parliament house. In 1924 it bought the building for parliamentary use. It has remained the parliament house of the Irish state. The Dukes of Leinster had by the early 20th century lost all their property and wealth. Their Carton House seat was sold (though 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 family now live in a smaller property in Ramsden, Oxfordshire.

The coat of arms of the Dukes of Leinster derives from the legend that John FitzGerald, 1st Earl of Kildare, as a baby in Woodstock Castle, was trapped in a fire when a pet monkey rescued him. The FitzGeralds then adopted a monkey as their crest (and later supporters) and occasionally use the additional motto Non immemor beneficii (Not forgetful of a helping hand). The motto "Crom A Boo" comes from the medieval Croom Castle and "Abu", meaning "up" in Irish; Crom Abu was the FitzGeralds' medieval warcry. Crom (Croom) and Shanet (Shanid) were two castles about 16 miles apart in County Limerick, one being the seat of the Geraldines of Kildare, and the other that of the Geraldines of Desmond, whose distinctive war cries were accordingly “Crom a boo” and “Shanet a boo.” In 1495 an act of Parliament was passed (10 Hen. 7. c. 20 (Ir)) “to abolish the words Crom a boo and Butler a boo.” The word “Abu” or “Aboo,” an exclamation of defiance, was the usual termination of the war cries in Ireland, as in a' buaidh, "to victory!" Saint Patrick's Saltire, a red saltire on a white field, may have been adapted from the duke's arms on the 1783 creation of the Order of Saint Patrick, of which the 2nd Duke of Leinster was the senior founder knight. Escutcheon: Argent a saltire gules. Crest: A monkey statant proper environed about the middle with a plain collar and chained or. Supporters: Two monkeys, environed and chained as in the crest. Motto: Crom a boo (Now it would be spelt "Crom Abu"). In English, "Up Croom", or "Croom to victory."