Thomas Pelham-Holles, 1st Duke of Newcastle
Thomas Pelham-Holles KG PC FRS (21 July 1693 – 17 November 1768) was 1st Duke of Newcastle upon Tyne and 1st Duke of Newcastle-under-Lyme. He was a British Whig statesman, and the third Prime Minister. He was Prime Minister for two separate terms. He is commonly known as the Duke of Newcastle.
His official life extended throughout the Whig supremacy of the 18th century. He was a protégé of Sir Robert Walpole, and served under him for more than 20 years until 1742. He held power with his brother, Prime Minister Henry Pelham, until 1754. By then he had served as a Secretary of State continuously for 30 years and dominated British foreign policy.
After Henry's death, the Duke of Newcastle was prime minister for six years in two separate periods. His first premiership (1754–1756) was not particularly notable: Newcastle partly caused the Seven Years' War, and his weak diplomacy cost him the premiership. After his second term (1757–1762), he served briefly in Lord Rockingham's ministry, before he retired from government. He was most effective as a deputy to a leader of greater ability, such as Walpole, his brother, or William Pitt the Elder.
- Basil Williams, The Whig Supremacy 1714–1760 (2nd ed. 1962) pp 352–53.