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Realistic Expansion for Divide et Impera grand campaign

It always bothered me when AI factions in TW games expanded into areas where they would never have been. So I made this submod for Divide et Impera that stops the AI from expanding into historically unrealistic areas. I wrote it because I wanted it for my own gameplay, but I might as well upload it for others to enjoy as well.

The script groups all factions into areas, like gaul, and every time a battle happens it checks whether a faction is in an area it shouldn't be in. If it is, it will get a battle loss via autoresolve modifications. Within these areas factions can evolve more or less freely, but they are restricted in size. Each faction has a region limit assigned to it that it may have at any point of the campaign. Before every battle, the combatants relative (over)expansion is compared, and battle bonuses are given so that factions don't become too big too soon. These limits are set individually for each faction, so for instance athens tends to stay at one region, while a gallic faction may get permission to expand to four or more regions.
The limits grow over time, so that factions are smaller in the beginning and can get bigger later. If you play as rome these region limits depend on your imperium level, so you can play as slow as you want and the AI will not grow too big. Once you get to germania after 200 turns, you will find germanic tribes there, not massilia. For non-roman factions region limits are tied to the turn number, as it is impossible to predict how many regions different players would have later in game. (If you like to change those values you can open the mod in a pack file manager[www.twcenter.net] and change the four TurnsForLevel variables in the beginning of the file to your liking. If you want to use regions as the limiting factor, then set UseRegionsForLevel to true and adjust the next four values to your intended campaign.) The script also checks that battle winners have an adjacent region, so they build continuous empires. The mod is mostly a limitation on the growth of the AI, which is why the file is still named "expansion_limiter".
The effects are randomized, so that campaigns are not always restricted by the same variables. To get more variation, now and then a faction gets special permission to escape some of its limitations. The AI can hopefully grow somewhat flexibly, but campaigns will be more similar than you are used to. For instance athens will never have five regions, because there is just no place for them to realistically have five regions. In rare cases they might conquer all of greece, but usually they have one region. So if you want a "alternate history" game where athens fights massilia in germania, then this mod is not for you. Then again, with this script being so heavily randomized now, it might well add variability to the campaign because it overrides the usual 'grooves' the AI follows.

Other features include the growth of factions that are supposed to be big in the grand campaign timeframe, such as carthage, parthia or pontus. In some campaigns parthia will grow to the size of a troublesome opponent for the romans, spanning the near east. Pontus should grow big enough to allow for a version of the mithridatic wars. A scripted peace between rome and carthage is declared after rome takes the mediterranean islands. This feature is currently turned off because people have been reporting problems with it. But I have just been testing it and it seems to work fine. So if you want to turn this feature on, then set the Car variable to true. But do this in the beginning of a campaign. And there is even a "Hannibal" army that will spawn in italy. (Although the general will probably not be named that, since the game assigns random ones.) Generally a lot is done to strengthen carthage and weaken massilia. Once the city of Carthago falls, the Carthaginian empire gets attacked by all it's neighbors and starts losing all battles, which means in the long term it gets defeated.
Overall the mod attempts to simulate realistic ownership of regions in the relevant timeframe, but particular scripting is only applied to a few factions. The submod is not trying to create a fully historic gameplay. It's still a sandbox TW game. I have mostly focused on the west, and some factions, particularly in the east, have received a less attention. These features are not long-term tested yet, as I have not had time to play a long campaign. The details still have to be fine-tuned as development proceeds. (When it does.) But the script should now be stable and fully debugged now.

Compatibility:
The mod should work with all DeI versions (unless possibly very old ones) and should keep working with future updates unless they change something very elementary. It was developed and tested with 1.3a and is fully compatible with it. I may not be around to update this submod, but unless DeI makes drastic changes the mod will keep working.
This script is only one file and it is very modular, meaning that it gets loaded "all or nothing", and as such it is unlikely to conflict with anything that doesn't use the same file. Few mods do, so it is fairly unlikely. Just load this mod above everything else in your load order, including your DeI parts or beta's. It doesn't matter how you sort this and other minor submods, as it is unlikely to conflict with them. This submod can safely be loaded all the way on top in your loading order.
It might even work with DeI conversion submods like Age of Hellenism, but I have not tested that. It won't work with vanilla or other full conversions such as Para Bellum. And the mod may not work properly in campaign multiplayer.
Enabling, disabling or updating the submod during a campaign is fully savegame compatible, but results might be weird if it is turned on late in a campaign. And if you hit end turn without it loaded, the game will forget your savegame-variables.

A log file named log.txt in your Total War Rome II folder will tell you about all AI battles that happen. If that file doesn't have content added to it, the script is not active.

Development is now about as far as I want to take it, and I won't update it for a while. You can still make feature suggestions, and I promise to read them some time, but it might be a while. Don't hesitate to post feedback of your experience. Let me know if some factions expansion seems wrong. It's better to join the DeI Discord, because I often don't understand what people mean if they make requests in short comments on this page. And if you send pictures of your campaign map after hundreds of turns, I will upload it here for others to see the results.

This is my most unique original work in Rome 2 modding. It might be the most complex battle script for R2TW. The other mods in my workshop are smaller tweaks that were designed to go along with it, so they fit together.