William Cavendish, 1st duke of Newcastle-upon-Tyne

William Cavendish was an English noble who became immensely wealthy through inheritances and royal favor. He was created Viscount Mansfield in 1620 and earl of Newcastle-upon-Tyne in 1628. On October 27, 1643, he was created marquess, and was advanced to a dukedom on March 16, 1665.

Before the English Civil War Cavendish was noted for his lavish hospitality, he spent £20,000 entertaining Charles I in the 1630s. From 1642 to 1644 he commanded army to fight for the royalist cause in the Civil War. His army was shattered at Marston Moor in 1644, and he went into exile.

At the Restoration, Newcastle returned to England and regained the greater part of his estates. According to his wife they lost £900,000 during the war, taking into account unrecovered lands, forced sales, woodlands and other sources of wealth plundered or destroyed, plus sixteen years of unpaid rents.

At his death, Cavendish was reckoned to be worth £300,000, about £7.8bn in 2010.