Sheffield, John, Duke of Buckinghamshire, son of the Earl of Mulgrave, whose title he succeeded to in 1658; served in the navy during the Dutch wars of Charles II.; held office under James II., and was by William III. created Marquis of Normanby; a staunch Tory in Anne's reign, he was rewarded with a dukedom, lost office through opposing Marlborough, but was reinstated after 1710, and in George I.'s reign worked in the Stuart interest; wrote an “Essay on Poetry,” &c. (1649‒1721).
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Sheffield * Sheikh