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 Armagnac, did not forget the offence, and Froissart speaks of it as the "first cause of hatred between him and the prince". A more powerful cause of this lord's discontent was the non-payment of an annual pension which had been granted him by Edward. About this time he agreed to marry Margaret of Bourbon, sister of the queen of France. The Black Prince was annoyed at this betrothal, and, his temper probably being soured by sickness and disappointment, behaved with rudeness to both D'Albret and his intended bride. On the other hand, Charles offered the lord the pension which he