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.

[2] The story features consulting detective Sherlock Holmes revealing to his friend and biographer Doctor Watson that for years now he has suspected many seemingly isolated crimes to actually all be the machinations of a single, vast, and subtle criminal organisation.

Holmes describes Moriarty's physical appearance to Watson, saying the professor is extremely tall and thin, clean-shaven, pale, and ascetic-looking.

[3] Holmes mentions that during their meeting, Moriarty remarked in surprise, "You have less frontal development than I should have expected," indicating the criminal believes in phrenology.

Watson does not witness the confrontation but arrives later to find signs of hand-to-hand combat occurring at the cliff edge near the waterfall, indicating the battle ended with both men falling to their deaths.

The gallery believed Adam Worth (the criminal who helped inspire Doyle to create Moriarty) was responsible, but was unable to prove the claim.

Doctor Watson, even when narrating, never meets Moriarty (only getting distant glimpses of him in "The Final Problem") and relies upon Holmes to relate accounts of the detective's feud with the criminal.

In "The Empty House", Holmes says Moriarty commissioned a powerful air gun from a blind German mechanic surnamed von Herder, a weapon later used by the professor's employee/acolyte Colonel Moran.

What makes Moriarty so dangerous is his extremely cunning intellect: He is a man of good birth and excellent education, endowed by nature with a phenomenal mathematical faculty.

But so aloof is he from general suspicion, so immune from criticism, so admirable in his management and self-effacement, that for those very words that you have uttered he could hale you to a court and emerge with your year's pension as a solatium for his wounded character.

While Doyle conceded to revealing that Holmes did not die during "The Final Problem" (as Watson mistakenly concludes), he chose not to undo Moriarty's death in a similar fashion.

[10] As established in Doyle's canon, Moriarty first gains recognition at the age of 21 for writing "a treatise upon the Binomial Theorem", which leads to his being awarded the Mathematical Chair at one of England's smaller universities.

[12][13] The 2005 pastiche novel Sherlock Holmes: The Unauthorized Biography also reports that Moriarty was born in Ireland, and states that he was employed as a professor by Durham University.

Watson mentions no forename but does refer to the name of another family member when he writes of "the recent letters in which Colonel James Moriarty defends the memory of his brother".

"[16] In Sherlock Holmes: A Drama in Four Acts, an 1899 stage play, of which Doyle was a co-author, the villain is named Professor Robert Moriarty.

[24] Newcomb was revered as a multitalented genius, with a special mastery of mathematics, and he had become internationally famous in the years before Doyle began writing his stories.

Carl Friedrich Gauss wrote a famous paper on the dynamics of an asteroid[26] in his early 20s, and was appointed to a chair partly on the strength of this result.

Srinivasa Ramanujan wrote about generalisations of the binomial theorem,[27] and earned a reputation as a genius by writing articles that confounded the best extant mathematicians.

[30][31] Jane Stanford, in That Irishman, suggests that Doyle borrowed some of the traits and background of the Fenian John O'Connor Power for his portrayal of Moriarty.

[34] It is averred that surviving Jesuit priests at the preparatory school Hodder Place, Stonyhurst, instantly recognised the physical description of Moriarty as that of the Rev.

[35] According to this hypothesis, Doyle as a private joke has Inspector MacDonald describe Moriarty: "He'd have made a grand meenister with his thin face and grey hair and his solemn-like way of talking.