The closest, current, popular author I can think of that writes what you describe is Guy Gavriel Kay (The Lions of al-Rassan , Sarantine Mosaic, The Last Light of the Sun, A Song for Arbonne). These stories are clearly from a very similar Earth History time period (the map in The Lions of al-Rassan is pretty much Spain and North Africa), but they are absolutely divorced from our history.
Unlike Alternate History, which basically has all the same "major players" with some key change, these places do not exist in our past. They are new though somewhat familir. There was no grand city called Sarantium, this is clearly a nod to ancient Rome. Mr. Kay says he started this because he had wonderful ideas for stories in these settings but did not want to be tied in anyway to a specific thread.
I've read most of his work - all of it excellent.