It was the words ‘By Tradition’ that caught me. Letters used to indicate the truth might not be what you think. The plaque would indicate that he died in the small chapel, stabbed while at prayer, possibly by the Duke of Gloucester – who would become Richard III. The official word from the Yorkists was that having lost the war, his crown, and his son, he died of displeasure and melancholy, but nobody really believed that.
The Lancasters’ tale of murder is the one that lasts and in case there was any doubt, there are those letters spelling ‘By Tradition’.