William Cavendish, 5th Duke of Devonshire, (14 December 1748 – 29 July 1811), was a British nobleman, aristocrat, and politician. He was the eldest son of William Cavendish, 4th Duke of Devonshire, by his wife, the heiress Lady Charlotte Boyle, suo jure Baroness Clifford, who brought in considerable money and estates to the Cavendish family. He was invited to join the Cabinet on three occasions, but declined each offer. He was Lord High Treasurer of Ireland and Governor of Cork, and Lord Lieutenant of Derbyshire.
Family and inheritance
He was married twice: first, to Lady Georgiana Spencer (1757–1806), daughter of John Spencer, 1st Earl Spencer; second, to Lady Elizabeth Foster, née Hervey (1759–1824), daughter of the 4th Earl of Bristol; Lady Elizabeth had been his mistress and his first wife's friend and confidante for more than twenty years.
First marriage
By his first wife, he had one son named (William Cavendish, 6th Duke of Devonshire, sometimes called "The Bachelor Duke", who succeeded him and who died unmarried in 1858), and two daughters: Lady Georgiana "Little G" Cavendish, later the Countess of Carlisle (wife of George Howard, 6th Earl of Carlisle), and Lady Harriet "Harryo" Cavendish, later the Countess Granville (wife of Lord Granville Leveson-Gower, who would be created 1st Earl Granville). Here Duchess Georgiana was prominent among the fashionable army wives and appeared in caricatures as 'Lady Gorget', the real colonel in full uniform, interviewing recruits for the regiment. The war ended with the Peace of Paris and the militia were disembodied in March 1783. Having recently taken over as Lord Lieutenant of Derbyshire himself, the Duke resigned the command in October and appointed his younger brother Lord George Henry Cavendish as colonel in his place.