John Holles, 1st Duke of Newcastle-upon-Tyne, KG, PC (9 January 1662 – 15 July 1711) was the son of the 3rd Earl of Clare and his wife Grace Pierrepont. Grace was daughter of The Hon. William Pierrepont and granddaughter of the 1st Earl of Kingston-upon-Hull.
The Duke was born in Edwinstowe, Nottinghamshire. On 1 March 1690, he married Lady Margaret Cavendish, a daughter of the 2nd Duke of Newcastle-upon-Tyne. They had one child, Lady Henrietta Cavendish Holles (1694–1755), who married the 2nd Earl of Oxford and Mortimer and was mother to Margaret Bentinck, Duchess of Portland.
Correspondence and estate records of John Holles, including letters to his wife, are held at the department of Manuscripts and Special Collections, The University of Nottingham, principally in the Holles Papers (Pw 2), part of the Portland (Welbeck) Collection.
A rivalry was formed between John and his sister, Elizabeth, when she married Christopher Vane, 1st Baron Barnard.[1]
Newcastle died in 1711 from injuries received in a fall from his horse while hunting near Welbeck.[2]