Archibald Montgomerie, 11th Earl of Eglinton (1726- 96), was the second son of the 9th Earl, and succeeded his brother, the 10th Earl, when he was murdered in 1769. Eglinton's maternal grandfather was Sir Archibald Kennedy, 1st Baronet of Culzean, and it may have been through this family connection that Adam was later introduced to the Earl of Cassillis, and received the major commission to work on Culzean Castle.

Eglinton was an military man, joining the army at the age of seventeen, and attaining the rank of Captain in 1744, Major in 1751, Colonel in 1762, Major-General in 1772, Lieutenant General in 1777, and General in 1793. He also served as MP for Ayr in 1761-68; Governor of Dumbarton Castle in 1764-82, and Edinburgh Castle in 1782-96; he was Deputy Ranger of Hyde and St James's Parks in 1766-68; and was a Scottish representative peer in 1776-96. In 1772 he married Lady Jean Lindsay (died 1778), daughter of the 21st Earl of Crawford, and then, in 1783 he married Frances Twysden (divorced 1788), daughter of Sir William Twysden, 6th Baronet of Roydon Hall, Kent.

After succeeding his brother, Eglinton made his town house at 79 Piccadilly. Piccadilly is a main arterial route into the city which had been built up during the seventeenth century. Number 79 (now 1 Stratton Street) has previously been identified as the work of Matthew Brettingham (1699-1769), but according to Colvin this attribution should be disregarded. Eglinton immediately commissioned Robert Adam to make designs for the interior decoration of the house, and designs for the ceilings of three rooms survive: the great room facing Piccadilly, the bow room, and the square room facing Stratton Street. It was reported by Bolton that at least one of these ceilings - certainly that for the great room - was executed and survived in 1922.

Eglinton must have sold the house on completion of Adam’s ceiling, as an attic storey was added in 1770-71 by Sir William Chambers (1722-96) for the 4th Earl Fitzwilliam. The house was demolished in 1929.

Literature:
A.T. Bolton, The architecture of Robert and James Adam, 1922, Volume II, Index pp. 51, 70; D. Stillman The decorative work of Robert Adam, 1966, pp. 101-102; D. King, The complete works of Robert & James Adam and unbuilt Adam, 2001, Volume I, pp. 307, 310; S. Bradley, and N. Pevsner, The buildings of England: London 6: Westminster, 2003, pp. 556-557; History of Parliament online: 'Montgomerie, Hon. Archibald (1726-96), of Minnoch, Ayr.'

Frances Sands, 2013