Ireland's parliament over the centuries had met in a number of locations, most notably in College Green, next to Trinity College Dublin. Its medieval parliament consisted of two Houses, a House of Commons and a House of Lords. Ireland's senior peer, the Earl of Kildare, had a seat in the Lords. Like all the aristocrats of the period, for the duration of the Social Season and parliamentary sessions, he and his family resided in state in a Dublin residence. (For the rest of the year, they used a number of country residences, notably Carton House in County Kildare.)
From the late eighteenth century Leinster House (then called Kildare House) was the Earl's official Dublin residence. When it was first built, it was located on the unfashionable and isolated south side of the city, far from the main locations of aristocratic residences, namely Ruthland (now Parnell) Square and Mountjoy Square. The Earl predicted that others; in succeeding decades Merrion Square and Fitzwilliam Square became the primary location of residences of the aristocracy, with many of their northside residences being sold. (They ended up as slums.) In the history of aristocratic residences in Dublin, no other mansion matched Kildare House for its sheer size or status. When the Earl was made the first Duke of Leinster, the family's Dublin residence was renamed Leinster House. (Its first and second floors - what Americans call second and third floors - were used as the floor model for the White House by its Irish architect, while the house itself was used as a model for the original stone-cut White House exterior.)
One famous member of the family who occasionally residenced in Leinster House was Lord Edward Fitzgerald, who became involved with Irish nationalism during the 1798 Rebellion, which cost him his life. With the passage of the Act of Union in 1800, Ireland ceased to have its own parliament. Without a House of Lords to attend, increasing numbers of aristocrats stopped coming to Dublin, selling off their Dublin residences, in many case to buy residences in London, where the new united parliament met. The Duke of Leinster sold Leinster House to the Royal Dublin Society. The society held its famous Spring Show and later its Dublin Horse Show on Leinster Lawn, a large open space between the house and Merrion Square. At the end of the nineteenth century, two new wings were added, to house the National Library of Ireland and the National Museum of Ireland.
The Anglo-Irish Treaty of 1921 provided for the creation of a self-governing Irish dominion, to be called the Irish Free State. As plans were made to bring the new state into being, the Provisional Government under W.T. Cosgrave sought a temporary venue for the meetings of the new Chamber of Deputies Dáil Éireann and Senate Seanad Éireann. Plans were made to turn the Royal Hospital, Kilmainham, an eighteenth century former soldiers' home in extensive parklands, into a full-time Parliament House. However as it was still under the control of the British Army, who had yet to withdraw from it, and the new Governor-General of the Irish Free State was due to deliver the Speech from the Throne opening parliament within weeks, it was decided to hire the main RDS Lecture Theatre attached to Leinster House for use in December 1922 as a temporary Dáil chamber. I
n 1924, due to financial constraints, plans to turn the Royal Hospital into a parliament house were abandoned; Leinster House instead was bought, pending the provision of a proper parliament house at some stage in the future. A new Senate or Seanad (pronounced 'sch-an-ad') chamber was created in Duke's old ballroom, while wings from the neighbouring Royal College of Science were taken over as used as Government Buildings. The entire Royal College of Science, which by then had been merged with University College Dublin, was subsequently taken over in 1990 and turned into a state of the art Government Buildings. Both the National Library and National Museum wings next to Leinster House remain used by as a library and museum and are not attached to the parliamentary complex. While plans were constantly made to provide a brand new parliament house (sites considered included the Phoenix Park and the Custom House, parliament has remained permanently located in Leinster House.
Since then, a number of extensions have been added, most recently in 2000, to provide adequate office space for 166 TDs, 60 senators, members of the press and other staff. Among the world leaders who have visited Leinster House to address joint sessions of the Oireachtas are US Presidents John F. Kennedy, Ronald Reagan and Bill Clinton, British Prime Minister Tony Blair, Australian Prime Minister Bob Hawke and French President Francois Mitterrand.
A number of monuments stand, or have stood, around Leinster House. Its Kildare Street frontage used to be dominated by a large statue of Queen Victoria, first unveiled by King Edward VII in 1904. The statue was removed in 1947 and was re-erected in the 1990s in Sydney, Australia. Facing its garden front on its Merrion Square side, stands a large triangular monument commemorating three founding figures of Irish independence, President of Dáil Éireann Arthur Griffith, who died in 1922, Michael Collins and Kevin O'Higgins, the Chairman of the Provisional Government and the Vice-President of the Executive Council (deputy prime minister), both of whom were assassinated, in 1922 and 1927 respectively. Another statue commemorates the Prince Consort, Prince Albert, husband of Queen Victoria, who held his major Irish Exhibition on Leinster Lawn in the 1850s.