William Cavendish-Bentinck, 3rd Duke of Portland

William Henry Cavendish Cavendish-Bentinck, 3rd Duke of Portland was a British Whig and then a Tory politician during the late Georgian era. He served as chancellor of the University of Oxford (1792–1809) and as Prime Minister of Great Britain (1783) and then of the United Kingdom (1807–1809). The gap of 23 years between his two terms as prime minister is the longest of any British prime minister. He is also an ancestor of Queen Elizabeth II, and therefore also King Charles III, through his great-granddaughter Cecilia Bowes-Lyon, Countess of Strathmore and Kinghorne.