Although Dr. Jekyll and Mr. Hyde is widely recognized as a monumental piece of fiction, Stevenson's concept of duality within human identity was not completely originally. In fact, he had encountered precursors to his tale long before he wrote the novel. Most frequently as influential to the development of Stevenson's work are . Hoffman's The Devil's Elixirs (1816), Thomas Jefferson Hogg's The Private Memoirs and Confessions of a Justified Sinner (1824), Edgar Allan Poe's William Wilson (1839), and most significantly, Theophile Gautier's Le Chevalier Double (1840). Gautier's story centers on the protagonist, Oluf, who has a double nature and leads a tormented life, much like Jekyll and Hyde.