Civilization IV Mods

This page offers modified XML files for the strategy game Sid Meier’s Civilization IV by Firaxis Games.

Civ4 exposes a large number of game parameters in XML files. You can change these parameters as you wish and put the modified XML files in a specific subdirectory of your (My) Documents folder. That way, every new “epic game” (a standard random map game which is not based on a scenario) will use your changed parameters.

Currently, you can download two different sets of modifications. They are stored in different XML files and can be applied independently or together, as you wish.

Important Note for Beyond the Sword — All modifications for this expansion are based on the current patch version 3.19 which changed many of the default XML files. You can find direct download links and a complete change log for the patch in this forum thread on the Apolyton Civilization Site.

Sadly, this patch once again contains a bunch of obvious bugs. I recommend that everyone download the Unofficial Patch for the patch, hosted by the Civilization Fanatics Forum.

Speaking of patches, I also suggest that you take a look at the The BUG Mod. This is a collection of excellent UI tweaks that make all kinds of important game information much more accessible. I wouldn’t want to run Civ4 without it!

Note — Make sure to install the BUG Mod after the unofficial patch, and let it overwrite any files that came with the latter. My BtS modifications listed below are all based on the file versions in the unofficial patch. (Fortunately, there is no overlap with the BUG Mod.)

Reduced Unit Busywork

This section applies only to the Beyond the Sword expansion. Some of the new features in this expansion tend to make gameplay rather laborious, compared to the basic game and the Warlords expansion.

All of the patches in this section come in small ZIP archives that contain any modified XML files nested inside their proper subdirectories. Unzip in (My) Documents\­My Games\­Beyond the Sword.

Weakened Spies

The new espionage system is based on Spy units that expend accumulated espionage points on a variety of missions. By default, both the Spy unit and many of the destructive mission types are very cheap. Late in the game, this can lead to hostile AI players incessantly spamming their opponents with hordes of spies attempting to destroy barracks, poison water supplies, and so on.

This tactic is not only immensely annoying but also contributes to the game’s sluggish performance. Most human players probably don’t want to emulate this behavior anyway, due to the massive micromanagement involved. While you can disable espionage entirely (as of patch version 3.17), some players may prefer a less radical approach. So I have raised the cost of spies and “harrassment” missions to discourage “spy spamming”. To further reduce micromanagement, spies move faster and counter-espionage lasts twice as long.

  • Changed build cost for Spy unit from 40 shields (equals Swordsman or Missionary) to 160 shields (equals Marine or Gunship), and changed movement from 1 to 2 squares.
  • Changed cost for Sabotage Improvement mission from 75 to 200 points.
  • Changed cost for Sabotage Building/Production/Project missions from 0 to 300 points. This fixed cost is added to the (unchanged) variable cost that depends on the item being destroyed.
  • Changed cost for Poison Water Supply and Foment Unhapiness missions from 120 to 300 points.
  • Changed cost for Counter-Espionage mission from 100 to 200 points, and changed duration from 10 to 20 turns.

These increased costs are not prohibitive, merely high enough to discourage a scattershot approach with multiple spy attacks per turn. The other mission types are either purely informational or already sufficiently expensive, and therefore remain unchanged. contains the new unit costs in CustomAssets\­xml\­units\­CIV4UnitInfos.xml, and the new mission costs in CustomAssets\­xml\­gameinfo\­CIV4EspionageMissionInfo.xml.

Eliminated Spies

Patch version 3.17 added a custom game option to disable espionage entirely, but the implementation of this new option is sadly clumsy: espionage points are converted into culture but otherwise remain in the game; you can still construct buildings that do nothing but produce espionage points; and you can still get random events based on the disabled espionage system. The one feature the option does completely remove is automatic intelligence gathering – which is also the one thing I like about the espionage system in Beyond the Sword!

So I made a small patch that provides an alternative (and hopefully more elegant) way to remove Spy units from the game. Espionage points still provide intelligence on foreign empires and cities, though nothing else. Along with spies, we also remove the two buildings whose sole purpose is to produce espionage points.

  • Eliminated Spy unit from the unit list.
  • Eliminated Security Bureau and Intelligence Agency from the building list.

Great Spies and Scotland Yard remain in the game since attempting to remove them produced crashes. However, without the Security Bureau and the Intelligence Agency your cities won’t generate Great Spies very often – and you can always use them to trigger a Golden Age, or to increase a city’s production.

Fortunately, the computer players don’t seem to have any trouble playing without spies. Overspending on espionage points could cripple AI performance since they are now fairly useless, but in my experience the AI doesn’t seem to do that. contains the new unit list in CustomAssets\­xml\­units\­CIV4UnitInfos.xml, and the new building list in CustomAssets\­xml\­buildings\­CIV4BuildingInfos.xml. Leave the new “Disable Espionage” option off when using this patch.

What About Executives?

You might also want to eliminate Corporate Executive units which can be a similar nuisance. I didn’t remove them in my patches since corporations provide little benefit without branches, and some quests are related to spreading corporations. However, if you want to try for yourself you can easily remove executives by commenting out their UnitInfo elements in CustomAssets\­xml\­units\­CIV4UnitInfos.xml. Their classes are called UNITCLASS_EXECUTIVE_1 through UNITCLASS_EXECUTIVE_7, and they are defined by the next seven UnitInfo elements following the one for the Spy unit.

Unit Upkeep

Army management has always been a huge timesink late in the game, and Beyond the Sword exacerbates this issue with the (re-)introduction of additional production facilities and unit types. AI players are prone to build as many units as their production capacity permits, which is a hundred or more even on small maps – and the human player must keep pace or risk losing the next war.

Civilization IV allows for unit-specific maintenance costs but this feature is unused by the default rules. In order to curb late-game unit proliferation, I have added a maintenance cost of 1-10 gold per turn for most military units. Maintenance costs are derived from build costs and start out with 1 gold for archers. Since archers cost 25 shields to build, a unit’s support cost usually equals 1/25th of its build cost.

  • Land units range from 1 (Archer, Axeman, Spearman, Chariot) to 9 (Modern Armor) extra gold per turn.
  • Naval units range from 2 (Galley, Trireme, Caravel) to 10 (Missile Cruiser, Stealth Destroyer) extra gold per turn.
  • Air units range from 3 (Airship) to 8 (Stealth Bomber) extra gold per turn.
  • Non-military units cost no extra gold: Settler, Worker, Scout, Spy, Executive, Missionary, Work Boat, Great Person.
  • Warrior units cost no extra gold since they are extremely weak and many nations start out with one.
  • Missile units cost only 1/250th of their build cost since they must be stockpiled to be useful: Guided Missile (free), Tactical Nuke (1 gold), ICBM (2 gold).

These costs also apply to nation-specific variants of each unit. The smaller army sizes enforced by the growing maintenance costs for upgraded units should reduce micromanagement, and may somewhat even the odds between players at different tech levels. Moreover, the added drain on the treasury makes the Space Race victory condition rather challenging, rather than a mere formality once you manage to survive until 2050.

Note — The AI cannot quite handle this patch. The computer players will nearly bankrupt themselves trying to build as many units as they can. I’m keeping the patch online anyway since increased unit upkeep is an obvious change that many player will want to try, but you may be disappointed by the results. contains the new unit costs as well as the changes listed under Weakened Spies. The new unit costs are stored in CustomAssets\­xml\­units\­CIV4UnitInfos.xml, and the new espionage mission costs are stored in CustomAssets\­xml\­gameinfo\­CIV4EspionageMissionInfo.xml.

Reduced AI Cheating

Civilization IV always allows its computer players some amount of cheating on all difficulty levels, even on and below the “Noble” level which supposedly puts human and AI players on an equal footing. This is both annoying and, in my opinion, unnecessary. The game seems challenging enough even with these cheats turned off.

So I made the following changes to the “Noble” difficulty level (all values apply to the basic game):

  • Lowered AI bonuses vs. animals & barbarians to match those for human players (iAIAnimalBonus -70 » -40, iAIBarbarianBonus -40 » -10)
  • Removed AI discounts for unit supply & upgrades (iAIUnitSupplyPercent 35 » 100, iAIUnitUpgradePercent 30 » 100)
  • Removed AI discounts for inflation & war weariness (iAIInflationPercent 70 » 100, iAIWarWearinessPercent 70 » 100)

Alan Au was kind enough to adapt these changes to the remaining difficulty levels, as shown in the following tables. The downloadable files contain the full set of changes.

Computer players on levels below “Noble” are not further penalized beyond disabling the listed cheats. For example, the “Settler” level pays 100% unit supply costs, just as on “Noble”. The bonuses vs. animals & barbarians were changed to match those for human players on the same level.

On levels above “Noble”, cheating is gradually re-introduced at a steeper grade, up to “Deity” which is identical to the unmodified game.

Original Release and Warlords Expansion

The values shown in the first table apply both to the basic game and to the Warlords expansion. The two XML files differ only in the hostility of wild animals (not shown here). Warlords increased iAnimalAttackProb for lower difficulty levels, and capped it at 90% for higher levels.

Animals Barbarians Unit Supply U. Upgrade Inflation War Wear.
Settler -70 -40 50 » 100 45 » 100 100 100
Chieftain -70 » -60 -40 » -30 45 » 100 40 » 100 90 » 100 90 » 100
Warlord -70 » -50 -40 » -20 40 » 100 35 » 100 80 » 100 80 » 100
Noble -70 » -40 -40 » -10 35 » 100 30 » 100 70 » 100 70 » 100
Prince -70 » -50 -40 » -20 30 » 90 25 » 85 60 » 85 60 » 85
Monarch -70 » -55 -40 » -25 25 » 70 20 » 65 50 » 65 50 » 65
Emperor -70 » -60 -40 » -30 20 » 50 15 » 45 40 » 50 40 » 50
Immortal -70 » -65 -40 » -35 15 » 30 10 » 25 30 » 35 30 » 35
Deity -70 -40 10 5 20 20

Beyond the Sword Expansion

The values shown in the second table apply only to Beyond the Sword.. This expansion features a greatly improved AI that cheats much less by default, as you can see. This XML file also contains a number of new entries (not shown here) that are unique to Beyond the Sword.

Animals Barbarians Unit Supply U. Upgrade Inflation War Wear.
Settler -40 -25 50 » 100 50 » 100 100 100
Chieftain -40 -25 50 » 100 50 » 100 90 » 100 90 » 100
Warlord -40 -25 » -20 50 » 100 50 » 100 80 » 100 80 » 100
Noble -40 -25 » -10 50 » 100 50 » 100 80 » 100 80 » 100
Prince -40 -25 » -10 50 » 90 50 » 90 80 » 100 80 » 90
Monarch -40 -25 » -10 50 » 80 50 » 80 80 » 95 75 » 80
Emperor -40 -25 » -15 50 » 70 50 » 70 80 » 90 70
Immortal -40 -25 » -20 50 » 60 50 » 60 80 » 85 60
Deity -40 -25 50 50 80 50

Download Mods

The modified XML file is available in three versions, one for the basic game and two for the expansion packs. All versions come in a small ZIP archive that contains the XML file nested inside its proper subdirectory: CustomAssets\­xml\­gameinfo\­CIV4HandicapInfo.xml.

  • contains the XML file for the basic game. Unzip in (My) Documents\­My Games\­Civilization.
  • contains the XML file for the Warlords expansion. Unzip in (My) Documents\­My Games\­Warlords.
  • contains the XML file for the Beyond the Sword expansion. Unzip in (My) Documents\­My Games\­Beyond the Sword.