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 the king's table and would not sit down with him, declaring that "he was not worthy to sit at table with so great a king or so valiant a man", and speaking many comfortable words to him, for which the French praised him highly. The next day the Black Prince continued his retreat on Bordeaux; he marched warily, but no one ventured to attack him. At Bordeaux, which the Black Prince reached on 2 October, he was received with much rejoicing, and he and his men tarried there through the winter and wasted in festivities the immense spoil they had