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
Royal coat of arms of the United Kingdom William I, King of Scots. Members of the British royal family are granted their own personal arms which are based on the Royal Arms. Only children and grandchildren in the male line of the monarch are entitled to arms in this fashion: the arms of children of the monarch are differenced with a three-point label; grandchildren of the monarch are differenced with a five-point label. An exception is made for the eldest son of the Prince of Wales, who bears a three-point label. Since 1911, the arms of the Prince of Wales also displays an inescutcheon of the ancient arms