Cornwall, Duchy of, consists of estates granted to the eldest son of the United Kingdom’s monarch. The monarch’s son receives the revenue from the estates after he reaches the age of 21. The estates are in Cornwall, Devon, Somerset, and elsewhere in the southwest of England. William, Prince of Wales, is the present Duke of Cornwall. The duchy was instituted in 1337 by King Edward III for his son Edward, the Black Prince. The duchy was rich because of its tin mines.
