ウィリアム・キャヴェンディッシュ＝ベンティンク
Bentinck was the third son of British Prime Minister William Cavendish-Bentinck, 3rd Duke of Portland and Lady Dorothy (1750–1794), only daughter of Prime Minister William Cavendish, 4th Duke of Devonshire. William Bentinck, 4th Duke of Portland, and Lord William Bentinck were his elder brothers.