Background
Stuart was the son of John Stuart, 3rd Earl of Bute and the former Mary Wortley Montagu, a granddaughter of the 1st Duke of Kingston-upon-Hull and great-granddaughter of the 1st Earl of Sandwich.
Stuart was the son of John Stuart, 3rd Earl of Bute and the former Mary Wortley Montagu, a granddaughter of the 1st Duke of Kingston-upon-Hull and great-granddaughter of the 1st Earl of Sandwich.
He was educated at Winchester and Oxford University, and around 1757 he began to be tutored by the later famous Scottish philosopher Adam Ferguson.
On 2 November 1775 he announced in the House of Commons his intention to introduce a bill to establish a militia in Scotland, and during the next few months James Boswell assisted in seeking support for the bill in Scotland. In March 1776 the bill was debated, but ultimately failed to pass. In 1776 Mount Stuart was elevated to the Peerage of Great Britain in his own right as Baron Cardiff, of Cardiff Castle in the County of Glamorgan.
Though this title was also used, he continued to be known by his courtesy title of Lord Mount Stuart.
(He ranked higher in the order of precedence as the heir to an earldom than he did as a substantive baron) In 1779 he was sworn of the Privy Council and was sent as an envoy to the court of Turin. He was ambassador to Spain in 1783.
He held the sinecure of Auditor of the imprests from 1781 until the abolition of the office in 1785, upon which he was paid £7000 compensation. He succeeded his father in the earldom in 1792.
In 1794 he was created Viscount Mountjoy, in the Isle of Wight, Earl of Windsor and Marquess of Bute.
(The Mountjoy and Windsor titles recognised the Barony of Mountjoy and Viscountcy of Windsor previously held by his father-in-law, the 2nd Viscount Windsor, which had both become extinct on Lord Windsor"s death in 1758) Lord Bute was inducted as a Fellow of the Royal Society on 12 December 1799. Lord Bute married the Honourable Charlotte Hickman-Windsor, daughter of Herbert Hickman-Windsor, 2nd Viscount Windsor, on 12 November 1766. They had several children:
John Stuart, Lord Mount Stuart (25 September 1767 – 22 January 1794), whose son succeeded as 2nd Marquess
Lord Evelyn Stuart (1773–1842), a colonel in the army
Lady Charlotte Stuart (c 1775 – 5 September 1847), married Sir William Homan, 1st Baronet
Lord Henry Stuart (7 June 1777 – 19 August 1809), father of Henry Villiers-Stuart, 1st Baron Stuart de Decies
Captain Lord William Stuart (18 November 1778 – 28 July 1814)
Rear-Admiral Lord George Stuart (1 March 1780 – 19 February 1841)
They had two children:
Lady Frances Stuart (d 29 March 1859)
Lord Dudley Coutts Stuart (11 January 1803 – 17 November 1854).
Royal Society; 12th Parliament of Great Britain. 13th Parliament of Great Britain. 14th Parliament of Great Britain]
Lord Mount Stuart was Tory Member of Parliament for Bossiney from 1766 to 1776.