i think i'd rather write fantasy stories, since i'm not a fan of history in the first place.
if i were to write one, it's probably way back during the dinosaur period. make an alternate version where the meteor extinction happened, but the smartest dinosaurs (velociraptor and troodon) survived, and they eventually evolved, along with humans, to be the other intelligent creature called the Dinomen. If both evolved, there'd be two races, one carnivorous and the other herbivorous. or they might even generalize to become omnivores.
they're smart enough for tool-usage and have complex social hierarchy, but unlike humans, their stamina wasn't as high for persistent hunting (since they had no sweat). their throwing abilities were also lesser (or maybe their tails could evoke deadly throws?). they also retained their cold-blood weakness.
due to the biblical teachings, they might be persecuted as the snake's descendant, which seduced Eve to get both Adam and Eve away from Eden. while they might actually be the snake's ancestors itself.
it might be nice to see them surviving against the more adaptable humans, and eventually standing on equal grounds, 'cuz they were about as smart. and their lives of hardship might make them even hardier.
of course, if I were to write it, I would change a lot of names since it's more to write a story, and not for historical accuracy.