Thomas Osborne, 4th Duke Of Leeds

Thomas Osborne, 4th Duke of Leeds, KG, PC, DL, FRS, was born on 6 November 1713 and died on 23 March 1789. Prior to inheriting his titles, he was styled Earl of Danby until 1729 and Marquess of Carmarthen until 1731. He was a member of the British peerage with roles in politics and the judiciary.

Born as the only surviving son of Peregrine Osborne, 3rd Duke of Leeds, and Elizabeth Harley, he was connected to notable noble families through his maternal lineage. Elizabeth Harley was the youngest daughter of Robert Harley, 1st Earl of Oxford and Earl Mortimer.

Osborne's education included attendance at Westminster School and Christ Church, Oxford. He matriculated at Oxford in 1731, the same year he succeeded his father as duke. He earned a Doctorate of Civil Law in 1738 and was elected a Fellow of the Royal Society in 1739.

In his career, Osborne served as a Lord of the Bedchamber beginning in 1748, and in November of that year, he was appointed Justice in Eyre south of Trent. He was made a Knight of the Order of the Garter in June 1749. He resigned from his position as Justice in Eyre in 1756 and was appointed Cofferer of the Household. In 1757, he was sworn into the Privy Council of Great Britain. He later became Justice in Eyre north of Trent in 1761, serving in this capacity until 1774. Additionally, he held the position of Deputy Lieutenant of the West Riding of Yorkshire.

On 26 June 1740, Osborne married Lady Mary Godolphin, who was the second daughter of Francis Godolphin, 2nd Earl of Godolphin, and Henrietta Godolphin, 2nd Duchess of Marlborough. They had four children, of whom three survived infancy: Harriot Osborne (born 13 November 1744 and died in November 1744), Thomas Osborne, Marquess of Carmarthen (born 5 October 1747), and Francis Godolphin Osborne, 5th Duke of Leeds (born 29 January 1751).

Thomas Osborne died at the age of 73 at St James's Square. He was buried in the Osborne family chapel at All Hallows Church in Harthill, South Yorkshire. His titles were inherited by his third and only surviving son, Francis.