So which is considered the oldest fandom? ( By what is considered a fandom by today’s standards) Sherlock or Star Trek?
Star Trek fandom basically created the idea of fan fiction, but Sherlock fandom nagged the writer to bring Sherlock back from the dead so the series didn’t end.
Sherlock or Star Trek???
*dusts off lectern*
Star Trek is generally considered the first western tv/film fandom. (The Man from UNCLE had a fandom slightly before then, but it didn’t persist or make a huge splash like Star Trek did).
Sherlock Holmes is generally considered the first western modern fandom in the sense that it’s the first piece of media to have a fandom amidst modern ideas of copyright. (There are other fandoms that came a bit earlier, especially with the serialized publication of novels, but, again, they didn’t persist or make a huge splash like Sherlock Holmes did.)
As many other people have pointed out in response to this post, fandom (aka participatory culture) has been a thing basically forever, both in terms of writing fanfiction (though it wasn’t called that) and in terms of having Feels and Opinions about stories and sharing them with the creators.
Modern notions of fandom are generally characterized by our concept of intellectual property ownership and the methods of media distribution, both of which create a divide between producers and fans that makes each identity more discrete.
(Sorry for being a bad academic and not citing anything here, but I’m on mobile and don’t feel like sourcing it all.)