Professor James Moriarty is a fictional character and criminal mastermind created by Sir Arthur Conan Doyle to be a formidable enemy for the author's fictional detective Sherlock Holmes. He was created primarily as a device by which Doyle could kill Holmes and end the hero's stories. Professor Moriarty first appears in the short story "The Adventure of the Final Problem", first published in The Strand Magazine in December 1893. He also plays a role in the final Sherlock Holmes novel The Valley of Fear, but without a direct appearance. Holmes mentions Moriarty in five other stories: "The Adventure of the Empty House", "The Adventure of the Norwood Builder", "The Adventure of the Missing Three-Quarter", "The Adventure of the Illustrious Client", and "His Last Bow". Moriarty is a criminal mastermind who uses his intelligence and resources to provide criminals with crime strategies and sometimes protection from the law, all in exchange for a fee or a cut of profit. Holmes likens Moriarty to a spider at the centre of a web and calls him the "Napoleon of crime", a phrase Doyle lifted from a Scotland Yard inspector referring to Adam Worth, a real-life criminal mastermind and one of the individuals upon whom the character of Moriarty was based. Despite appearing only twice in Doyle's original stories, later adaptations and pastiches have given Moriarty greater prominence, often using him as the main antagonist, and treated him as Sherlock Holmes' archenemy.