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 with his father on 12 October 1347, took part in the jousts and other festivities of the court, and was invested by the king with the new order of the Garter (1348). The Black Prince shared in the king's expedition to Calais in the last days of 1349, came to the rescue of his father, and when the combat was over and the king and his prisoners sat down to feast, he and the other English knights served the king and his guests at the first course and then sat down to meat at another table. When the king embarked