Yes, there is something odd about the chronology of the two stories in which he figures, "The Final Problem" and The Valley of Fear.
And yes, he seems to have been involved in only two of the sixty published cases — which hardly justifies the popular impression (based perhaps on films and parodies) that Holmes and Moriarty duelled throughout their long careers.
The drawing at right is by Sidney Paget, an illustration for the original publication of "The Final Problem" in 1893.
Note the spelling: Moriarty. Not Moriarity, not Moriaty, not Morrity, not even, as one parodist rendered it, Arty Morty!
Copyright © Chris Redmond 2014