....well the record isnt definitive on Richard 11...after being deposed and imprisoned by Henry Bolingbroke who bacame Henry IV, the first of the Lamcastrian Kings, it is said that he just gave up,quit eating etc, and "died of pure melancholy"...although it is suspected that Henry's minions may have hastened that along somewhat, since as long as he was still alive he posed a threat to the legitimacy of Henry's reign
It's easy to quit eating when your food supply is dependent on a jailer whose interests would be served if you conveniently died without showing any marks of foul play....
btt