Duchy of Cornwall from Duchy income, assisted by Grants-in-aid from the Queen. If there is no duke (for example, if the monarch does not have any male children) the duchy income reverts to the monarch and the annual Sovereign Grant is reduced annually by the amount of the duchy's income. The duchy was established on 17 March 1337 by the Royal Great Charter out of the former Earldom of Cornwall by Edward III for his son, Edward, Prince of Wales, the "Black Prince", who became the first Duke of Cornwall. The charter established that the Duke of Cornwall is to be the eldest
Edward the Black Prince possible that this is where the title had its origins. The French soldier Philippe de Mézières refers to Edward as the greatest of the "black boars" – those aggressors who had done so much to disrupt relations within Christendom. Other French writers made similar associations, and Peter Hoskins reports that an oral tradition of "L'Homme Noir", who had passed by with an army, survived in southern France until recent years. In Shakespeare's "Henry V", the King of France alludes to "that black name, Edward, Black Prince of Wales". John Speed reported in 1611 that the Black Prince was so named