Professor James Moriarty is a fictional character who is the best known antagonist (and nemesis) of the detective Sherlock Holmes. Widely considered to be the first true example of a supervillain, Moriarty is a criminal mastermind, described by Holmes as the "Napoleon of Crime." (T. S. Eliot would later use the same phrase, in homage, to describe Macavity in Old Possum's Book of Practical Cats.) Sir Arthur Conan Doyle, the creator of Sherlock Holmes, lifted the phrase from a real Scotland Yard inspector who was referring to Adam Worth, a true-life (though non-violent) model for Moriarty.

Source: Wikipedia