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 next year (1356) on another chevauchée he ravaged Auvergne, Limousin, and Berry but failed to take Bourges. He offered terms of peace to King John II of France, who had outflanked him near Poitiers, but refused to surrender himself as the price of their acceptance. This led to the Battle of Poitiers where his army routed the French and took King John prisoner. The year after Poitiers, the Black Prince returned to England. In 1360 he negotiated the treaty of Bretigny. He was created Prince of Aquitaine and Gascony in 1362, but his suzerainty was not recognised by the