The Right Honourable James Stuart Mackenzie (1719-1800) was the only brother of John Stuart, 3rd Earl of Bute. He served as MP for Argyllshire in 1742-47, Buteshire in 1747-54, Ayr Burghs in 1754-61, and Ross-shire in 1761-80. Moreover, he was Envoy to Turin in 1758-61, and Lord Privy Seal of Scotland in 1763-65 and 1766-1800. In 1749 he married his cousin, Lady Elizabeth Campbell, daughter of the 2nd Duke of Argyll. He assumed the name of Mackenzie in 1739, having succeeded to the estate of his great grandfather, Sir George Mackenzie of Rosehaugh.

In 1766 Stuart Mackenzie commissioned Robert Adam to make designs for a castle, a tower and a church. It is likely that Adam had been chosen as the architect for these projects owing to his preferment by Stuart Mackenzie's brother, Lord Bute. Despite this, none of Adam's designs for Stuart Mackenzie were executed, and it is not known for what estate they were intended. According to King it is unlikely that these designs were made for Rosenhaugh, as Stuart Mackenzie had sold the majority of his holdings there in 1752.

Literature:
A.T. Bolton, The architecture of Robert and James Adam, 1992, Volume II, Index pp. 56, 79; D. King, The complete works of Robert & James Adam and unbuilt Adam, 2001, Volume II, pp. 67, 165, 246; Yale Edition, Horace Walpole's correspondence, 2011, Volume 22, p. 302; E. Haden-Guest, 'Stuart Mackenzie, Hon. James (?1719-1800), of Rosehaugh, Ross and Belmont, Angus', History of Parliament online, 2012

Frances Sands, 2012