The Byzantine Empire is the succesor to rome and a single authority, but there is danger on the horrison, Turks, Civil Unrest, and a confused Succesion system lead the 2nd Rome further and further into decline, however if you are able to wrangle the rowdy Empire and hold Greece and Anatolia together, the rewards will be great, and you will be the most powerful man in Europe, maybe one day even you can call yourselves Roman again