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 been one of the prince's trusted friends. When the Black Prince heard of the surrender of Limoges to the French, he swore "by the soul of his father" that he would have the place again and would make the inhabitants pay dearly for their treachery. He set out from Cognac with an army of about 4,000 men. Due to his sickness he was unable to mount his horse, and was carried in a litter. During the siege of Limoges, the prince was determined to take the town and ordered the undermining of its walls. On 19 September, his miners succeeded