Winning by faction, yes.
But mainly - winning by alliance points in this winning faction, which is way harder. To achieve that players at times will have to sacrifice for example some powers that give nice bonus to the alliance to the region that gives most points, make strategic decisions whether they should go let's say for Carthago (Unique boots - 20 points) or Hibernia (200 points) early in the game to be top-lead.
Prefer the hibernia