In OTL, the Roman Empire got split into east and west. How can I make it so that the Roman Empire get split into a North (pars borealis) and a South (pars australis) instead of an east-west split? The North gets Italy, the Balkans, Gaul, Anatolia, and Britannia. The South gets Sicily, Iberia, Sardinia, North Africa, and other islands in the Mediterranean. What might be the effects of each empire in this scenario. How will this effect culture and the rest of history with a North-South split?