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Imperator Rome: Diplomacy Tips

Imperator: Rome is the newest grand strategy title from Paradox Development Studio. Set in the tumultuous centuries from Alexander’s Successor Empires in the East to the foundation of the Roman Empire, Imperator: Rome invites you to relive the pageantry and challenges of empire building in the classical era. Manage your population, keep an eye out for treachery, and keep faith with your gods.

Other Imperator Rome Guides:

Imperator Rome Diplomacy Tips


  • Countries are ranked by the number of cities they control: City State, Local Power, Regional Power, Major Power and Great Power.
  • Diplomacy is limited by diplomatic range. You can extend it via inventions and by climbing the ranks as world’s power. As of 1.0 it seems to be off at times, especially on the eastern side of the map.
  • Diplomatic options available to you change with your rank.
  • Only countries of the same rank can be allies. For example a Regional Power can’t ally with a Local Power, it can only guarantee it.
  • Opinion penalty given to you by aggressive expansion will be the main limiting factor in your diplomacy.
  • Aggressive expansion decays over time by 0.20% of its current value when you’re at peace. It may be a lot or very little depending on how much of it you have.
  • Additional aggressive expansion decay can be provided by your government officials, inventions or even trade goods. That kind works both at peace and at war.
  • You can slowly improve opinion of other country by up to base 50 points by paying a base cost of 50 oratory cost. Both the amount and the cost can be changed via various modifiers.
  • Increasing improve opinion maximum also increases the pace in which the opinion is gained.
  • Increasing opinion is twice as effective towards your subjects.
  • You can also improve opinion by 25 by sending a gift, but keep in mind that it is capped at 25 so subsequent gifts will only refresh the bonus.
  • There is number of subject types providing different bonuses, but keep in mind that neither Tributaries not Tribal Vassals can be integrated.
  • Other subject can be integrated after 10 years and reaching 190 opinion.
  • Integration takes at base speed 4 months per every pop in the subject country.
  • Base integration speed can be doubled by picking Subjugative Stance and for every 5 points of Diplomatic Reputation.
  • Each point of Diplomatic Reputation increases the likelihood that out diplomatic offer will be accepted by 1. It’s not nearly as powerful as in EU4. It also speeds up subject integration.
  • Each country has a diplomatic stance that can be change for the base cost of 100 oratory power in the Diplomacy tab (F6).
  • Bellicose Stance will allow you to save 20 oratory power on claim creation, but it’s main use is lowering the warscore cost in peace deals which may allow you to take more land at the same time. Keep that option in mind when putting together a peace deal.
  • Appeasing Stance doubles your innate aggressive expansion decay (it only happens at peace!) and lowers the cost of improving relations by 12 oratory power a piece. It seems most useful after a long conquering spree when we want to be able to do trade with the world again.
  • Mercantile Stance significantly increase the commerce income and allows to save 7 points of civic power per trade route created while it’s active. Good choice when we’re struggling with money and outright necessery one if we plan on creating a lot of trade routes (See: Trade).
  • Subjugative Stance, as mentioned above, doubles the base speed of subject integration.
  • You can fabricate a claim on a province for the base cost of 200 oratory power.
  • You can declare a war without a claim, but it will cost you 2 stability. It can be worth if oratory power is more valuable to you than the religious one (it usually is).
  • “Show Superiority” cassus belli will make all the land taken in the peace deal cost 3 times the normal amount of warscore.
  • Taking land of a subject state in a war costs double to warscore.
  • Declaring the war with a claim lowers the warscore cost by 25%.
  • You need at least 10 warscore to be able to demand anything in a peace deal.
  • “Length of the war” will make peacing out quickly difficult, unless you achieve total victory.
  • To be able to demand a province in a peace deal you need to conquer its capital (marked by a white column and mentioned on the peace deal screen) and all the forts in it. You don’t need to conquer any other city.
  • You can also demand single cities, but you need to directly control all of them.
  • You cannot demand territory you won’t be able to reach via land or sea (military access and subjects or allies do NOT count).
  • You cannot fabricate a claim on such lands either, otherwise you’re just limited by diplomatic range.


  • Each country follows one of the military traditions. Few countries can change those via scripted events, but the vast majority is stuck with what they got.
  • Each tradition provides a starting bonus you can check by hovering over a picture in the top right corner of the Military tab (F3).
  • You can only select a tradition of the one above it has been taken. You don’t have to focus on a single column tho.
  • Base cost of the tradition is 800 military points and increases by 50% for every tradition already selected.
  • Each level of Military Advances (See: Research) lowers the cost of military traditions by 25%, so it may be wise to stockpile military points for a longer while if the bonuses aren’t immediately needed.
  • Traditions on top of various combat bonuses provide access to unique abilities and tactics for our armies.
  • Armies are made of various cohorts, each with different cost, requirements, statistics, abilities and combat match-ups vs. one-another.
  • Some cohorts require specific resources or even traditions to recruit.
  • If you lack the required trade resource needed to recruit a cohort you won’t be able to replenish the ones you already have.
  • Armies move at the speed of its slowest units, so and army of 10 light cavalry will move at the speed of 4 while the same army with 1 additional light infantry will move at speed of 2.
  • Maneuver determines how many tiles to the side a cohort can attack during the battle. Unit with maneuver of 1 will only be able to fight enemy right in front of it as well as its neighbors on both sides, while a cohort with maneuver of 5 can reach up to 11 enemy cohorts (1 in front and 5 on each side).
  • More numerous army with high maneuver units on the flanks can quickly overwhelm a superior but shorter enemy line.
  • Keep in mind the bonuses and debuffs different cohorts suffer against other unit types. Your heavy infantry may laugh at enemy light infantry, but their horse archers is an entirely different thing.
  • In the top right corner of the army screen you can switch a tactic used by that army.
  • Each nation has access to 5+ tactics and new ones can be sometimes unlocked via traditions.
  • Try to counter an enemy tactic or at least not allow an enemy to counter yours – it may turn a potential win into a costly defeat.
  • You can hover over tactic effectiveness number below the tactic’s icon to see what constitutes it.
  • Tactic effectiveness is of secondary importance as it only comes into effect if you managed to counter and is utterly worthless in 2 other cases.
  • Keep an eye on river crossings and terrain, those can cause harsh penalties for the attacker in combat.
  • An army besieging a fort is considered an attacker in every battle in the province.
  • You need to have at least 5000 men per level of the fort to besiege it. Keep attrition in mind.
  • Check if the enemy fort isn’t undermanned. Sometimes assaulting it (base cost: 20 military power) may be a better option.
  • Only certain unit types can assault the city.
  • Forts provide a zone of control to all cities around themselves. Those can be viewed using fortification mapmode (Ctrl+T).
  • An army in a zone of control can only move the the adjacent fort or back to the city it came from.
  • Battle result indicators on the map can be useful, but they aren’t always right.
  • Army (and navy) without an assigned commander will suffer a 25% morale penalty.
  • Military skill of the commander is extremely important. 3 point difference in commander skill with offset attacking across the river into mountains.
  • Only 1, best commander will actually lead in the battle.

It’s end. I hope “Imperator Rome: Diplomacy Tips” helps you. Feel free to contribute the topic. If you have also comments or suggestions, comment us.

Written by Emnel

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