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Revision as of 20:27, 2 December 2019 by (talk) (Reorganizational: Removed paragraph about being unable to detach loyal cohorts as that is no longer the case.)
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In Imperator:Rome, an army represents a portion of the military power of a state. Historically Rome referred to an army as a legion. An army serves as a container for cohorts and is represented by a pawn on the map that can be moved around on its own. War is waged with armies.

Armies can be created or destroyed at any time for no cost by moving cohorts around.

Army Features:

Unit abilities

What we call unit-abilities in Imperator can be one of three categories:


  • Create New Unit - Allows you to create a new unit and transfer cohorts/ships to it, or back.
  • Consolidate - Merges manpower depleted cohorts of the same type, and then removes empty cohorts.
  • Detach Siege - Leaves behind a large enough force to siege or occupy the current city.
  • Split Half - Splits the Unit in Half.
  • Recruit To - Opens up the recruit window, so you can recruit cohorts/ships directly to this unit. They will automatically march and merge to this unit.
  • Disband - For when you don’t want that unit anymore. This action has a one-time high monetary cost.

Drop Down Menus

  • Select Objective - Can Select an Objective for this unit, and it will perform it without further input from you.
  • Select Tactics - Affects combat effectiveness in certain circumstances (see Combat Tactics)


  • Allow Attachment - Allow other nations units to attach to this one.
  • Unit Reorganisation - Double Maintenance and Slow movement speed, but unit reinforcing and morale recovery is much faster. Without using this, units recover slower than in previous games.
  • Force March - Heavier Attrition and No morale recovery while moving much faster.

Some toggles have a small military power cost.


  • Attach/Detach to Unit – Attach/Detach to another unit present in the city.
  • Shattered Retreat - Gives the order for the unit to perform a shattered retreat. This is handy if you want to save the remnants of your army trapped deep in enemy territory, or when you are cut off by hostile Forts.
  • Desecrate Holy Site – Spend Religious power.png Religious Power in another nations capital to reduce their omen power for a long time.
  • Raise Levies – Spend Military Power to get more cohorts to your unit.
  • Build Road – Spend 10 Military power.png Military Power to build a road towards the next city the army moves to. This is the cheapest and fastest way to build roads in the game.
  • Construct Border Fort – grants hold of an unowned city, instantaneously adding a fort (with 100 garrison) and 1 freeman pop of your state's culture and state's religion to it in exchange for 2000 Manpower.png manpower and xxx Military power.png Military Power. One of the cohorts in the army performing the action will gain loyalty to its current military leader!
    • must have researched at least Technology lvl x in the military field and the military tradition xxx purchased.
    • Army must have a leader assigned
    • Army must contain at least 5 cohorts, and at least one cohort must not have a loyalty towards any character
    • Annexed city must be adjacent to one of your own cities
    • None of the adjacent cities may contain a fort!
  • Military Colonies – Spend Military Power to create a freeman pop of your culture/religion in the current city.
  • Raid City – Spend Military Power to get gold and manpower from an enemy city. It is possible to do this when you have taken control over hostile territory, giving you money and manpower, while hurting that province in growth, output and commerce for 5 years.

Some of these are unlocked by different military traditions, and some of them are always available.


A constant factor in warfare are the non-combat related losses in a conflict. Armies moving through hostile territory, or just areas unable to support them in general, will often suffer as many, often more, than ones directly involved in combat.

In Imperator locations will have a supply limit (shown as a value next to the cauldron in the screenshot above), which is the size of army that the land can support without suffering attrition. Base Attrition is shown by the Skull in the province interface above.

Weather and hostile terrain can also directly increase attrition of present armies. An army in a desert city will always suffer 1% attrition from it, as will armies in locations with harsh winter or at sea. Together with the mountain passes, roads and other features of the map this means that you will have to pay closer attention to the map when on campaign. Minimum attrition means that an unsafe route might be more punishing than what you are used to.

The automatic path-finding will prefer shorter movement times and low attrition when possible, but at times you might want to cross that desert to reach the battlefield you want.

Attrition ticks on the 1st of every month. If an army is in transit and arrives somewhere on the 1st, it will get attrition based on the destination.

The attrition weight of an army is equal to the the accumulated values for all cohorts it is comprised of plus Modifiers. The value is compared to the current supply limit of the city the army is located in.

Army movement

Armies moves from one city to another city. Adjacent cities have a calculated distance between them and armies move a base distance per day (subject to modifiers).

Unit Objectives

Unit objectives allow you to assign individual armies orders to act autonomously under the control of the AI. Unit objectives are a way to outsource the management of some armies to the AI, essentially using the same things that the AI itself uses to control its armies and navies. You can at any time select an objective for each army or navy under player control (or several units at once, in which case the objective applies separately to each one currently), which enables AI for said unit, making it automatically take actions almost as if it was controlled by an AI country.

Available Objectives

  • No Objective: The unit remains idle unless ordered by the player. This is the default for players.
  • Independent Operations: The unit acts independently, attacking enemy armies/navies, occupying enemy cities, etc. as it sees fit.
  • Naval Landing: If there is at least one available and sufficiently large navy which has Naval Landing selected, ordering an army to move to a city that's accessible only by sea will make this navy pick up that army and ship it to that city. (Armies will default to traveling by land if a land route is available however, ctr + click order and the army will be transported by sea instead)
  • Defend Borders: The army will stay inside friendly borders, fighting enemy armies that enter and retaking occupied cities.
  • Hunt Fleets: The navy will seek out enemy fleets and attempt to engage them.
  • Fight Rebels: Army will focus on destroying rebel (slave revolt) armies and retaking rebel-occupied cities.
  • Reconnaissance: Patrols across the country's borders or nearby seas reporting enemy movements.
  • Keep in Reserve: The army will stay within the country's borders and actively avoid contact with the enemy unless superior.

Special Objectives

There are also many Unit Objectives that you cannot pick but that you may still encounter. Disloyal Generals will make use of a specific unit objective where they essentially do what they themselves want to. Making you unable to order them around or do things like send them to a certain death. Likewise Mercenaries that you do not pay will stop taking your orders and operate on their own. There is also special logic for Slave Revolts, where rebel stacks will seek out the closest rich city to attempt to loot and set free more of their kin.


In Imperator Mercenary armies are always present, spread out over the map, using their own banner and the unit graphics of the local culture. As long as a mercenary army is not hired by anyone it will also not count towards the supply limit in the city they are located. Mercenary armies all have their own General, to whom all the troops are loyal.

At times Mercenary groups played a decisive part in conflicts, as did their tendency to abandon an employer that could not pay them.

Mercenary Overview Screen

Here you can at all times see what Mercenaries exist (sorted by Proximity) and who has hired them. It also displays the monthly cost of employing each Mercenary group.

Hiring Mercenaries

Hiring a Mercenary regiment comes at a one time cost of 50 Military Power, but also obliges you to pay their upkeep for the duration of their employment (at a rate 400% more expensive than what one of your own armies would cost).

Hiring the army immediately brings it under your control, but does not move it to your territory. Instead, hired mercenary armies hired outside of your territory will begin in a state of exile, so they can be brought to your territory to then be used in whatever conflict you intend. Mercenaries also start out at 0 morale.

Any Mercenary company in diplomatic range can be hired as long as you can pay to disband them, but their high upkeep means that hiring an army far from your conflict could get expensive as you would be paying their upkeep from the day they are hired.

Once no longer exiled, the mercenary army will act as any other army under your control, except for the fact that you cannot remove its leader, or remove any units. They will use your military bonuses, you can alter their deployment and their military tactics.

Disbanding Mercenaries

As with any army you can also disband a mercenary army at any time it is not in battle. Their increased upkeep cost will however also mean that disbanding them can be quite costly.

Once disbanded the mercenary army will again be considered available for hire, and it will begin its journey back to its home location.

Mercenary Princes

Sometimes disenfranchised heirs may supplement the Mercenary company list.


Should you not be able to pay your mercenaries several negative consequences may arise. For instance that mercenary band might offer to join the opposing side in an ongoing war.

Domestic policy State Characters Attributes Culture Government Laws National ideas Rebellion Religion Technology
Economic policy Buildings Economy Population Trade Trade goods
Provinces Region Province Territories Colonization
Military Military traditions Army Siege Assault Land units Land warfare Naval warfare
Foreign policy Treaties Warfare Casus belli Diplomacy Subject nations Barbarians
Script Events Decisions Missions