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 were traitors. On the morning of the 3 April the prince's army marched from Navarrete, and all dismounted while they were yet some distance from Henry's army. The vanguard, in which were three thousand men-at-arms, both English and Bretons, was led by Lancaster, Chandos, Calveley, and Clisson; the right division was commanded by Armagnac and other Gascon lords; the left, in which some German mercenaries marched with the Gascons, by the Jean, Captal de Buch and the Count of Foix; and the rear or main battle by the prince, with three thousand lances, and with the prince was Peter and,