"died a lingering death on that rock"
Napoleon on His Deathbed by Horace Vernet
Public DomainNapoleon on His Deathbed by Horace Vernet

 

 It is possible that Napoleon died of wallpaper poisoning. After his death it was suspected that he had been poisoned, and in modern times, tests on locks of his hair show traces of arsenic, which was used as an ingredient in green wallpaper paint during the nineteenth century; many people died of poisoning, known as 'Gosio's disease', as a result. Specimens of Napoleon's green wallpaper from Longwood House on St Helena show that it did contain arsenic. Although it was probably not enough to kill him outright, it would have exacerbated the effects of the stomach ulcer from which he suffered.