Henry Cavendish, 2nd Duke of Newcastle upon Tyne, KG, PC, styled Lord Henry Cavendish until 1659 and Viscount Mansfield from 1659 to 1676, was an English politician. He sat in the House of Commons from 1660 until 1676, when he inherited the dukedom.

William Cavendish, 1st Duke of Newcastle upon Tyne, KG, KB, PC, who after 1665 styled himself as Prince William Cavendish, was an English courtier and supporter of the arts. He was a renowned horse breeder, as well as being patron of the playwright Ben Jonson and the intellectual group known as the Welbeck Circle.