So, historical fiction and alternate history.
The thing about alternate history is that (to generalize and whatnot) the creator takes a moment of difference in the past and then extrapolates a future from that moment of difference. Historical fiction has moments of difference from the historical record; it is, after all, fiction. But there is not (generally, again, generalizing) the extrapolation of widening difference that alternate history has. Instead, at the end of a historical fiction, we can extrapolate from that moment to our own; the future of the people in the book is our present, not some alternate present.
In The Rabbi of Swat, Peter Levine begins with a thing that didn’t happen: John McGraw arranges to have a rookie pitcher named Morrie Ginsberg brought up partway through 1927, the first Jew to play Major League Baseball. Then he adds a thing we know wasn’t true: he ‘reveals’ that Zack Taylor, the peripatetic catcher who has joined the Giants that year, is actually a Jew passing under a false name and history. These two changes bring about more changes over the summer and autumn, although Mr. Levine is more interested in baseball and Brooklyn than in bigger historical or cultural issues. So the primary difference in the historical record is that the Giants win the pennant.
And then there’s a world series, where Morrie Ginsberg pitches Game Seven against the Yankees, while Arnold Rothstein and a bunch of Jewish gangsters… look, it doesn’t really matter, does it? The Giants win the pennant! The Giants win the pennant! The Giants win the pennant!
Tolerabimus quod tolerare debemus,
-Vardibidian.