You mean, Arthur Conan Doyle, who told American actor William Gilette that he could essentially do anything with the character?
I’m just saying….ACD canon is great and all, and it’s fine if you like to stick to that, but there’s room for a little bit of everything, honestly, because by the end of it all, ACD was frankly sick of Sherlock Holmes. The reason he brought back Sherlock Holmes from the dead was because of the Sherlockians of 1899 and their black armbands (think of it as the predecessor to our “I believe in Sherlock Holmes” movement).
Having said all of that, I’m really hoping that we DO see Mary in the series.
My sincerest hope is that “wedding” is a red herring. Everyone’s freaking out about John possibly marrying Mary Morstan, and everyone forgets that Sherlock Holmes, bless his amoral little heart, got engaged to a maid in CHAS in order to learn the layout of the house the maid worked in SO HE COULD BURGLE IT. And also Sherlock Holmes wore sneakers.
I seem to remember ACD being somewhat bemused by the idea of a concrete overarching continuity among the stories. The whole idea of “canon” to mean “the stuff that actually definitely happened in a notional world” and not “a body of work” is kind of a fandom construct.
(Source: sherlock--confessions)
