Alternate History

So Boneshaker was my first steampunk novel, and I enjoyed the idea of alternate history as a sub genre of science fiction. I guess its just the history major in me. I'm not the biggest fan of the Victorian era, and absolutely don't believe the Civil War could ever last 17 or so years, but it was fun nonetheless. Since I'm still relatively new to science fiction literature, I was wondering if there are any other eras in history that have science fiction literature? Mostly what I read is futuristic, but I'm just curious if there is anything else out there history wise other than the Victorian era.