well, in 312 AD, there aren't much 'factions' left. no more greeks, macedon, carthage, egypt, iberia. playing rome then isn't even a challenge, it's just mopping up.
look here http://www.phatnav.com/wiki/index.ph...e=Roman_Empire
what ( IMO) would be interessting is to be able to play rome right after the marius reform, so you can instanly wield cohorts. like is beiing done for RTR6.0
Bookmarks