Thomas Pelham-Holles 1st Duke of Newcastle upon Tyne and 1st Duke of Newcastle-under-Lyne KG PC (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.