James Moriarty

James Moriarty was the arch-enemy of Sherlock Holmes.

History
In order to investigate Baron Maupertuis, Moriarty used the alias O'Connor and donned a ginger wig as part of his disguise. He also wrote a paper on the mathematics of folding higher dimensions. (PROSE: All-Consuming Fire) Moriarty died in 1893. (PROSE: The Found World)

Contradicting other accounts, Moriarty also seemed to exist in the Land of Fiction, suggesting he was a fictional character. (COMIC: Character Assassin)

The Eleventh Doctor, while dressed like Sherlock Holmes, once compared the Great Intelligence to Moriarty, calling it "the clever one." (TV: The Snowmen)

Behind the scenes

 * Moriarty has been played by Paul Freeman in the film Without a Clue, Philip Locke on stage and Ronald Pickup in a radio play.
 * Doctor Who producer Barry Letts and script editor Terrance Dicks confirmed that the Master was devised as the Moriarty to the Doctor's Sherlock Holmes. (DOC: Life on Earth)