William Cavendish, 1st Duke of Newcastle-upon-Tyne KG KB PC (6 December 1592 – 25 December 1676) was an English polymath and aristocrat, having been a poet, equestrian, playwright, swordsman, politician, architect, diplomat and soldier

At first a courtier of James I of England, he would later strike up friendships with Charles I of England and his wife Henrietta Maria whom he hosted lavish banquets for. He was created Marquess of Newcastle-upon-Tyne and entrusted with the education of the royal couple's son, the future Charles II of England. Cavendish was a staunch royalist helping to fund the king in his Bishops' Wars and then during the English Civil War he was made a general for the fight in the North of England against the roundheads. He was at first successful, but part of his force was defeated at Winceby by Oliver Cromwell in 1643, and after his defeat with Prince Rupert at Marston Moor in 1644 he retired to the Continent.After the defeat at Marston Moor, Cavendish went into self-imposed exile, only returning with the English Restoration where he was made a duke.