William Cavendish, 4th Duke of Devonshire, English politician, Prime Minister of the United Kingdom (b. 1720)
William Cavendish, 4th Duke of Devonshire, (8 May 1720 – 2 October 1764), styled Lord Cavendish before 1729, and Marquess of Hartington between 1729 and 1755, was a British Whig statesman and nobleman who was briefly nominal Prime Minister of Great Britain. He was the first son of William Cavendish, 3rd Duke of Devonshire and his wife, Lady Catherine (née Hoskins).