Recently I went back to an older rule set I used to use in conjunction with my ancients ruleset to generate a campaign. It is based on a Roman/Carthage kind of war, although it can accomidate as many players as there is space.
It consists of a sea map sheet (blue hexes) that isomorphic "continents" are place. As seen from the pictures, I have several "continents" and 2 major power continents. I place one of the random non-major power continents in the middle of the map. Each player randomly chooses one of the unpicked non-major power continents and lays it down so that it matches at least 3 hexes of another continent. It continues until only the major power continents are left, which each player takes one and places it as far away from the other major power as possible.
The end result is a wandering continent with minor powers to conquer in order for the two major powers to come to grips. Next, I have to generate the cities. On each continent (and each region in that continent (e.g Corinth), a number of cities are randomly place by die roll (the circled numbers)- in the case of Corinth, it gets 1 city. For the major powers, I give them 5 cities, they randomly place then by die roll, then can adjust up to 3 of them.
I also created counters to represent the two major powers and any minors they may fight along the way- btw they print better than they look in the exported powerpoint slide (I make most of my counters in Powerpoint and double side them all).
The rules handle all the production and maintenence of the major powers, wars with minor powers. supply, naval units etc etc. Turns are monthly, with weather generated (which pricipally effects supply). The real beauty of the system is that it can be used to generate meaningful ancient battles (that fit my own ancient rule system of course), both land and naval in a unified framework. I can also fight the battle in boardgame form instead of setting up miniature terrain, troops etc. Its the best of both worlds (miniature and boardgame).
I can start at "year Zero" and play until exhausted or one major power triumphs. It's also open-ended- I can have more than 2 major powers by adding a new counterset for that major power and a continent for them.
I came. I saw. I conquered. Indeed........