Just a note about Roman organization for anybody wanting to take up the Empires.

These are not necessarily two separate Empires, though they kind of are? It is difficult to express. Emperor Augustus claimed legitimacy through his adoption by Caesar (Caesar wasn't an Emperor btw, or at least not to traditional reckoning which places Augustus as the first Emperor). Augustus than took the name "Augustus" (He had been Octavian before) and reorganized the government so that he had clear and indisputable control, since all of the provinces with military postings were under his control. He didn't come out and say "I am Emperor now", but rather started calling himself first citizen. Following a tradition unwittingly started by Caesar, Augustus would give the title of "Caesar" to his chosen heir. Augustus eventually gives the title of Caesar to his son-in-law Tiberius, who becomes Augustus when Augustus dies and gives the title of Caesar to his nephew Caligula, who passes it to his uncle Claudius, who passes it to his son-in-law Nero. Even after coups and civil wars, this tradition continues. 

And this started a trend. The Emperor adopts the name "Augustus" and gives the name "Caesar" to his heir. When (or if) that heir comes to power, they adopt the title of Augustus and give the name "Caesar" to the new heir. Since the Imperial title wasn't hereditary, the name Caesar could be given to whoever the Emperor chose. Sometimes this was a son , sometimes it was a relative, and sometimes it was a colleague. 

By the fourth century, Rome was sort of a has-been city. The capital was initially moved to Milan, and eventually Constantinople, since the east was where most of the action and the money was. Despite this move, the Empire split into two pieces several times where there would be two Augustus's and two Caesars, in which case the Western Augustus would settle in Milan. Eventually, they moved to Ravenna, which is where the Western Capital was located when the Western Empire fell.

In this scenario, I figured I'd orient it where there is just one Empire being ruled by the Emperor and his heir. The other three sections, the "Dioceses" represent the larger political regions of the Empire and would be subject to the Emperor. The Emperor, or "Augustus", rules from Constantinople. Caesar, the heir, rules from Italy.

Now, if it were me as Caesar the west, I would move the capital to Venice. The Western Empire fell before Venice was anything more than a few refugees in a marsh, but the location would be excellent in terms of defense. It is impossible to attack without a navy, it is located near the north where threats to Italy would be coming from, and it can be supplied from the sea. 

TL;DR: Augustus is supreme, Caesar is his heir. The Western part of the Empire is second to the East. The West should probably move its capital to Venice. 

Also, I am planning on taking up the "Diocese Oriens" if anybody is wondering.

[@AYoungWarthog] I would be willing to help with the OOC. Maybe give some overviews of some basic details about the historical factions.