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 Prince sustained a heavy loss in the death of his friend Chandos. Several efforts were made by Edward to conciliate the Gascon lords, but they were fruitless and can only have served to weaken the prince's authority. It is probable that John of Gaunt was working against him at the English court, and when he was sent out in the summer to help his elder brother, he came with such extensive powers that he almost seemed as though he had come to supersede him. In the spring Charles raised two large armies for the invasion of Aquitaine; one, under the