William Cavendish, the son of the 8th Baron of Ogle, was born in 1592. He served as tutor to the future Charles II from 1638 to 1641. He also fought for Charles I during the Bishop Wars in Scotland.

Cavendish joined the Cavaliers on the outbreak of the Civil War and in 1642 was appointed Commander-in-Chief in the counties of northern England. At first Cavendish was very successful but after the defeat at Marston Moor in July, 1644, he went into exile.

Cavendish returned to England at the Restoration and in 1665 Charles II granted him the title, 1st Duke of Newcastle. He wrote several plays and was the author of two books on horsemanship.

William Cavendish, 1st Duke of Newcastle, died in 1676.