Buckingham, Or Buckinghamshire, John Sheffield, duke of, an English statesman and poet, born in 1649, died Feb. 24, 1721. He succeeded his father Edmund Sheffield as third earl of Mulgrave in 1658, early acquired some distinction in the navy and army, became a knight of the garter and a gentleman of the bedchamber under Charles II., served a little while under Turenne, commanded the expedition to Tangier, was a member of the privy council and lord chamberlain under James II., and acquired under King William (1694) the title of marquis of Normanby. According to Walpole, he was an early lover of Queen Anne, who appointed him lord privy seal, and created him duke of Normanby and of the county of Buckingham in 1703. Several editions of the works of Buckingham appeared between 1723 and 1740. His " Essay upon Poetry " was at first published both in English and Latin, and translated in 1749 into French. The highest compliment conferred upon his " Essay on Satire" was the castigation inflicted in consequence of it, at the instigation of the earl of Rochester, upon Dryden, who was supposed to have had something to do with the authorship; but this is denied by Walter Scott, who says that "Dryden's verses must have shone among Mulgrave's as gold beside copper." Dr. Johnson praises his memoirs as lively and agreeable, but does not speak so highly of his other works.

He was eulogized by Roscommon, Pope, and Dryden, and erected a monument to Dryden in Westminster abbey. On the death of his son Edmund (1735) the ducal title became extinct. His third wife, the countess of Anglesea, was a natural daughter of James II. Her grandson, Sir Constantine Phipps, inherited the Mulgrave and Normanby titles and estates. The duke left an illegitimate son, who was called Charles Herbert, assumed the name of Sheffield, and became a baronet; he was the great-grandfather of the present Sir Robert Sheffield.