<P> Edward III of England created the first English dukedom by naming his eldest son Edward, the Black Prince, as Duke of Cornwall in 1337, after he lost his own title of Duke of Normandy . Upon the death of the Black Prince, the duchy of Cornwall passed to his nine - year - old son, who would eventually succeed his grandfather as Richard II . </P> <P> The title of Duke of Lancaster was created by Edward III in 1351 for Henry of Grosmont, but became extinct upon the duke's death in 1361 . The following year, Edward III bestowed the title (2nd creation) on his fourth son, John of Gaunt, who was also married to the first duke's daughter . On the same day Edward III also created his second son, Lionel of Antwerp, as Duke of Clarence . </P> <P> All five of Edward III's surviving sons eventually became dukes . In 1385, ten years after their father's death, his heir Richard II created dukedoms for his last two uncles on the same day . Thomas of Woodstock was named Duke of Gloucester and Edmund of Langley became Duke of York, thereby founding the House of York, which later fought for the throne with John of Gaunt's Lancastrian descendants during the Wars of the Roses . </P> <P> By 1483, a total of 16 ducal titles had been created: Cornwall, Lancaster, Clarence, Gloucester, York, Ireland, Hereford, Aumale, Exeter, Surrey, Norfolk, Bedford, Somerset, Buckingham, Warwick and Suffolk . Some became extinct, others had multiple creations, and some had merged with the crown upon the holder's accession to the throne . When the Plantagenet dynasty came to an end at the Battle of Bosworth Field on 22 August 1485, only four ducal titles remained extant, of which two were now permanently associated with the crown . John de la Pole was Duke of Suffolk and John Howard was Duke of Norfolk (2nd creation), while the duchy of Cornwall was reserved as a title and source of income for the eldest son of the sovereign, and the duchy of Lancaster was now held by the monarch . </P>

What is the job of duke and duchess