A letter that has lain unread for over 600 years is forcing a rethink of a 14th Century prince with a controversial reputation. He was the superstar of his age, winning his spurs in battle aged just 16. But the reputation of Edward of Woodstock - or the Black Prince, as he has become known to history - is still the subject of the same type of dispute that rages over the reputations of Richard III and Oliver Cromwell.
A persistent theory runs that Edward's nickname refers to the cruelty he inflicted upon the French during the Hundred Years War - the dynastic struggle for the crown of France. The blackest stain upon Edward's reputation is the sack of the French town of Limoges in September 1370.