August 26th, 1346 saw the Battle of Crecy, with the English battling the French for Edward III's claim to the French throne. Edward's son (Edward, Prince of Wales) was known as the black prince, and he distinguished himself in this battle. It is possible that this battle included the first use of cannon.
There is a connection between the black prince and Scott's Ivanhoe. Ivanhoe was the name of one of the three manors that were forfeited by a John Hampden, who had unwisely struck the black prince, possibly during a jousting match.