Thomas Pelham-Holles, 1st Duke of Newcastle upon Tyne and 1st Duke of Newcastle-under-Lyne (21 July 1693 – 17 November 1768) was a British Whig statesman, whose official life extended throughout the Whig supremacy of the 18th century. He is commonly known as the Duke of Newcastle.
A protégé of Sir Robert Walpole, he served under him for more than twenty years, until 1742. He held power with his brother, Henry Pelham (the Prime Minister of Great Britain), until 1754. He had at this point served as a Secretary of State continuously for thirty years—dominating British foreign policy.
After Henry's death the Duke held his late brother's position for six years, in two separate periods. While his first premiership was not particularly notable, Newcastle precipitated the Seven Years' War, which would cause his resignation from his high position.[citation needed] After his second term as Prime Minister, he served for a short while in Lord Rockingham's ministry, before retiring from government. Few politicians in British history matched his skills and industry in using patronage to maintain power over long stretches of time. He was most effective, however, as a deputy to a leader of greater ability, such as Walpole, his brother, or Pitt.
Historian Harry Dickinson says that he became:
notorious for his fussiness and fretfulness, his petty jealousies, his reluctance to accept responsibility for his actions, and his inability to pursue any political objective to his own satisfaction or to the nations profit.... Many modern historians have depicted him as the epitome of unredeemed mediocrity and as a veritable buffoon in office.