The history of Dublin's South Georgian Core dates back to the 1700s when the lands were owned by Richard Fitzwilliam, 6th Viscount of Fitzwilliam (24 July 1711 – 25 May 1776), an Irish Peer. In 1744 he married Catherine Decker, who was the daughter of a wealthy Dutch businessman. They lived between the Decker estate in Surrey and the Fitzwilliam estate in Mount Merrion, Co Dublin.

In 1745, Richard Fitzwilliam was contacted by Thomas Fitzgerald, the Earl of Kildare, asking him to lease some land near St. Stephen’s Green. On this site Thomas Fitzgerald built his new home called Kildare House. This former palatial home is now Leinster House, the home of the modern Irish parliament. The resounding success of the completion of Kildare House in 1748 generated an interest in developing the area further. Richard Fitzwilliam contracted the architect John Ensor, who designed an outline of Merrion Square and the houses on the adjacent street.

The houses were uniform in design. Each house was constructed with 3.5 stories high over basement with sash windows. All the buildings were to be used solely for residential purposes, no commercial enterprises were permitted. The first leases were sold and building commenced in 1762. From commencement the strict terms of the lease ensured that the houses were constructed to a very high and consistent standard thus creating prestigious luxurious residential homes. The bricks used in the front of the houses were produced in the Fitzwilliam owned brickworks on the Merrion Estate. The granite used to construct the pillars, window surrounds and sills, and front steps were sourced from the granite quarries in Ticknock, also owned by Fitzwilliam. The houses stood on wide open streets, with Georgian Squares acting as communal gardens for the residents. In addition the houses had long rear gardens and stable lanes to the rear. The uniformity of the houses’ facades hid the wealth of opulent decoration that lay within with many of the houses containing ornate plasterwork and spectacular staircases and fireplaces.

In 1776, the 6th Viscount of Fitzwilliam died, being buried in Donnybrook Cemetery. His successor was his son Richard, 7th Viscount (c. 22 August 1745 - 1816). In 1789, he commissioned a design to develop Fitzwilliam Square. This project moved more slowly due to the changing political landscape at the time. And the 7th Viscount died in 1816 unmarried and without legitimate heirs. So while Fitzwilliam Square was laid out by surveyors in 1791, war and the Act of Union impeded its development and the last house was only completed in 1828, more than three decades after the first. 

In the two centuries since there have been many changes in use and occupancy and development in the area. While many Georgian Townhouses are now offices a portion remain in residential use. The mews lanes in the area that originally contained stable buildings are  now heavily residential, interspersed with small businesses.  And many small apartment blocks and new office buildings have been added to the area over time. While many Georgian Townhouses were demolished in the 20th century enough survive in the South Georgian Core for it to act as a showcase of our built heritage.