Duke of Clarence is a title which has been traditionally awarded to junior members of the British Royal family. All three creations were in the Peerage of England.
The title was first granted to Lionel of Antwerp, the second son of King Edward III, in 1362. Since he died without sons, the title became extinct. The title was again created in favour of Thomas of Lancaster, the second son of King Henry IV, in 1412. Upon his death, too, the title became extinct. The last creation in the Peerage of England was for George Plantagenet, brother of King Edward IV, in 1461. The Duke forfeited his title in 1478, after he had been convicted of treason against his brother. He allegedly met his end (according to William Shakespeare) by being drowned in a butt of Malmsey.
A fourth creation in England was suggested and planned to take effect; the title of Duke of Clarence was going to be given to Lord Guilford Dudley, husband of Lady Jane Grey, upon her coronation, as she declined to make her husband king consort. However, she was deposed before this could take effect.
Two double dukedoms, of Clarence and St Andrews and of Clarence and Avondale were later created for British royal princes. The title also took the form of an earldom for Queen Victoria's son Prince Leopold, Duke of Albany and his son Prince Charles Edward, the Clarence earldom being a subsidiary title.