John Stuart, 1st Marquess Of Bute

John Stuart, 1st Marquess of Bute PC, FRS (30 June 1744 – 16 November 1814), was a British nobleman, coalfield owner, diplomat, and politician. He was born at Mount Stuart House on the Isle of Bute, the son of John Stuart, 3rd Earl of Bute, who served as Prime Minister, and his wife, Mary Wortley Montagu.

Stuart received education at Harrow School and Winchester College, followed by attendance at the University of Oxford, where he was privately tutored by James Bladen. An honorary D.C.L. degree was conferred upon him by Oxford in 1793. Around 1757, he began tutelage under philosopher Adam Ferguson.

He was elected as a Tory Member of Parliament for Bossiney in a by-election in 1766 and held seat through subsequent general elections in 1768 and 1774. On 2 November 1775, he announced in the House of Commons plans to introduce a bill to establish a militia in Scotland. The bill was debated in March 1776 but ultimately did not pass. He vacated his seat in 1776 after being elevated to the Peerage of Great Britain as Baron Cardiff, of Cardiff Castle in Glamorgan. Despite this, he was known by his courtesy title, Lord Mount Stuart, which ranked higher in precedence than his substantive title of baron.

In his public service, he served as Lord Lieutenant of Glamorgan from 1772 to 1793, and from 1794 until his death, being the first Lord Lieutenant of Buteshire. He commanded the Glamorgan Militia as Lieutenant-Colonel Commandant from 1778. In 1779, he was sworn into the Privy Council and served as an envoy to Turin. In 1783, he served as ambassador to Spain. He held the sinecure of Auditor of the Imprests from 1781 until its abolition in 1785, receiving £7,000 in compensation.

Stuart succeeded his father as Earl of Bute in 1792. Three years later, he was elevated to several peerages: Viscount Mountjoy, Earl of Windsor, and Marquess of Bute (1794). These titles recognized previous baronies and viscounts held by his family and father-in-law. He was inducted as a Fellow of the Royal Society on 12 December 1799.

His familial relationships included marriages to two notable women. In 1766, he married the Honourable Charlotte Hickman-Windsor, daughter of Herbert Hickman-Windsor, 2nd Viscount Windsor; they had seven sons and two daughters. Their children included John Stuart, Lord Mount Stuart, and Lady Charlotte Stuart. Charlotte died in 1800. Later that same year, he married Frances Coutts, daughter of Thomas Coutts; they had two children, Lady Frances Stuart and Lord Dudley Coutts Stuart. Frances Coutts outlived Stuart, dying in 1832.

In 1799, his family was estimated to be the second-wealthiest small family unit in Britain, owning property valued at approximately £4.2 million at the time, primarily in coal and agricultural land.