Thomas Thynne, 1st Marquess Of Bath

Thomas Thynne, 1st Marquess of Bath, was born on 13 September 1734. He was the eldest son of Thomas Thynne, 2nd Viscount Weymouth, and Louisa Carteret. His mother was a daughter of John Carteret, 2nd Earl Granville, and her family had connections to the Earldom of Bath, which became extinct in 1711 upon the death of William Granville, 3rd Earl of Bath.

The Thynne family descends from Sir John Thynne (circa 1515–1580), who built Longleat House in Wiltshire and acquired extensive estates following the Dissolution of the Monasteries. Sir John Thynne served as comptroller of the household under Queen Elizabeth I. A notable ancestor, Thomas Thynne (1648–1682), was known for his wealth and was famously murdered in London.

In January 1751, Thynne succeeded his father as the 3rd Viscount Weymouth. He held the office of Lord Lieutenant of Ireland briefly in 1765, although he never visited Ireland. Thynne gained prominence in British politics and was appointed Secretary of State for the Northern Department in January 1768. During the unrest caused by John Wilkes and the Middlesex election of 1768, Thynne responded promptly, which led to Wilkes libeling him and being expelled from the House of Commons.

In late 1768, Thynne was transferred to serve as Secretary of State for the Southern Department. He resigned from this position in December 1770 amidst the Falklands Crisis of 1770, a dispute with Spain over the Falkland Islands. He later returned to the same office in November 1775, overseeing both the Northern and Southern Departments temporarily in 1779, during the early years of the American War of Independence. Thynne resigned from these offices in autumn 1779.

In 1781, he became High Steward of the Royal Town of Sutton Coldfield, a position he held until his death. Thynne was elevated to Marquess of Bath in 1789, a new title, since the Earldom of Bath was not available at that time.

In 1759, Thynne married Lady Elizabeth Bentinck, daughter of William Bentinck, 2nd Duke of Portland, and Margaret Bentinck, Duchess of Portland. They had three sons and five daughters. Their children included Lady Louisa Thynne, Lady Henrietta Thynne, Lady Sophia Thynne, Thomas Thynne, 2nd Marquess of Bath, Lady Maria Thynne, Lady Isabella Thynne, and George Thynne, 2nd Baron Carteret. George inherited the title of Baron Carteret through a special remainder from his paternal uncle, Henry Carteret.

Thomas Thynne, 1st Marquess of Bath, died on 19 November 1796. His legacy includes Weymouth Street in Marylebone, named after him, on land once owned by his wife's family.