Subject nations

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Vassalized.png Subject nations, or vassals, are countries in a subservient relationship to another state, paying tribute or fulfilling commercial or military obligations to their overlord in return for protection from other states. They are restricted in their diplomatic actions, especially with countries other than their overlord, and certain subject types can be integrated directly into their overlord.

General rules[edit]

Each kind of subject state is different but there are general guidelines all subject states must follow.

  • All subject types Tribute income.png pay some sort of resource to their overlord, with the exact type and amount depending on the subject type.
  • Other than for trade, a subject can never enter into diplomatic agreements with other countries. except for allowing Has military access.png military access.
  • When a country becomes a subject, all their treaties with other countries are broken.
    • Use this property to your advantage by diplomatically forcing your target's allies to become your subjects before declaring war.
  • The overlord and subject will always have Has military access.png military access to each other's territory.
  • Subjects always have Has military access.png military access to the territory of other subjects of the same overlord.
  • A subject can always leave a subject relationship by declaring War.png war on their overlord. They cannot declare war on any other country.
  • Overlords will always be called to War.png war and become the war leader if one of their subjects are attacked.
  • If the overlord and its subject state are both involved in the same war, the overlord can always transfer occupation to and from any of their subject states and can annex territory on their behalf for half of the Aggressive expansion.png aggressive expansion (compared to if the overlord was annexing the territory directly).
  • For subjects which can be called into war, if their loyalty is too low, they can refuse to join their overlord's war.

Subject nation types[edit]


  • Requirements: These conditions must be true for this relationship to be possible.
  • Payment: The subject makes this payment to the overlord on a monthly basis.
  • Dip. slot: Whether a subject of this type contributes to the overlord's diplomatic relations limit.
  • Join wars: Whether a subject of this type is automatically called into the overlord's wars, if it is loyal.
  • Integrate: Whether the overlord can integrate the subject.
  • Break: Whether the subject can break the relationship through a diplomatic action (i.e. without a war).
  • Limit dip.: Whether the overlord limits the subject's diplomatic interactions.
  • Effects: Modifiers given to the subject and overlord, if any. If an overlord has multiple subjects of the same (or different) type, the modifiers will stack.

Subject type Requirements Tribute income.png Tribute Diplomatic relations.png Dip. slot War.png Join wars Integrating Integrate Break Limit dip. Effects
  • None
Cost 15% of income No No No Yes Yes None
  • Overlord is NOT a Tribe
  • Overlord has at least Local.png 20 territories
  • Subject has no more than Local.png 10 territories
  • Subject and overlord are in the same Policy cultural assimilation.png culture group
Manpower.png 15% of monthly manpower gain No Yes Yes No Yes Subject:
  • Army maintenance cost.png −10% Army Maintenance Cost
  • Citizen happiness −4% National Citizen Happiness
Tribal vassal
  • Subject is a tribe and overlord is not
  • Overlord's Civilization.png capital civilization value is higher than in the subject's capital
  • Overlord has fewer than 10 tribal vassals
Manpower.png 15% of monthly manpower gain No No No Yes Yes Overlord:
  • Tribesman happiness +4 National tribesmen happiness


  • Civilization.png +10 Max civilization
  • Global monthly civilization.png +0.01 Monthly civilization change
Satrapy Cost 25% of income Yes Yes Yes No Yes Overlord:
  • Legitimacy.png +2% Monthly legitimacy
Client state
  • Neither subject nor overlord is tribal
  • Subject has fewer than Local.png 150 territories
Cost 25% of income Yes Yes Yes No Yes Subject:
  • Popularity.png −5% Ruler popularity gain
  • Commerce value.png +10% National commerce income
  • Can only export to overlord.
  • Only by event/mission
Cost 15% of income No No No No Yes Overlord:
  • Commerce value.png +5% National commerce income


  • Commerce value.png +10% National commerce income
  • Loyalty.png +25 Loyalty to overlord
Mercenary State
  • Only through the unique Flag of Syracusae Syracusae Create mercenary state.png Create Mercenary State action
Cost 10% of income Yes Yes Yes No Yes Overlord:
  • Mercenary maintenance.png -3% Mercenary Army Maintenance


  • Global manpower modifier.png +12.5% National Manpower
  • Army maintenance cost.png -20% Army Maintenance Cost


Perhaps the most basic subject type in the game is the tributary. This is a loose relationship where the subject is simply looking for protection in exchange for tribute. Unlike most other subject types, the subject can at any time cancel a tributary relationship if there is no Truce.png truce, the only risk being that the former overlord will get a Casus belli.png casus belli for the slight on their honor. This will happen for AI-controlled countries if there any of the following conditions are met:

  • Has less than Subject loyalty.png 35 loyalty
  • Has Land combat.png more army cohorts than the overlord
  • Has less than Subject loyalty.png 50 loyalty, owns more than Local.png 3 territories, and borders the overlord

Tributaries with very high Subject loyalty.png loyalty may instead approach their overlord to pursue a closer relationship and become a client state. This event can only trigger once per country.


A feudatory is a state that has obligated itself to follow the lead of a larger and more influential country in the same culture group. Historically these are countries that would often have been part of some sort of league with their overlord’s other subjects, in many ways this is a privileged subject type, if one with large obligations.

Feudatories provide Manpower.png manpower to their overlord and are expected to take part in their wars. Historical examples are the Flag of Rome Roman Socii, the Punic cities of North Africa under Flag of Carthage Carthage, or the city leagues in Aegean under the Flag of Antigonid Kingdom Antigonids.

Tribal vassal[edit]

A tribal vassal is a tribal kingdom, chiefdom or federation that has a close relationship to a nearby stronger civilized state. For the tribal state this means a significantly easier route towards civilizing, as it will increase both the countrywide level of Civilization.png civilization and the growth of it in all their territories. The tribal state in turn pays with its Manpower.png manpower to the overlord who, will also promise to protect them. Historical subjects of this type would be the Numidian kingdoms subject to Flag of Carthage Carthage and various Flag of Rome Roman clients on the later imperial border. When a vassal tribe adopts a civilized form of government, it will become a tributary.

Client state[edit]

Client states are in some ways more tightly integrated with their overlord, but unlike the feudatories they are not necessarily of the same culture and they do not enjoy a privileged status in the same way, paying a large part of their Wealth income instead of providing Manpower.png manpower. A client king is separated from a governor mostly by his level of autonomy and having local ties to the ruled country. Client states can be created by subjugating existing countries like most other subject types, or released from the country's currently owned provinces in the Top bar overview.png Nation Overview.


Satrapies are a special type of subject that is only available if the junior party has Military tradition.png Persian military traditions. The fundamental unit of organization in Persia since the time of the 20px Median and Flag of Achaemenid Empire Achaemenid empires, a satrap is in some ways similar to a governor but is expected to have greater authority, bigger obligations, and a more imposing realm. As having powerful satraps is an expectation in the east a few of them will also help with maintaining the Legitimacy.png legitimacy for their overlord kingdoms. Flag of Bactria Bactria, Flag of Parthia Parthia, and Flag of Arachosia Arachosia start off as satrapies of the Flag of Seleukid Empire Seleukid Empire, while Flag of Cappadocia Cappadocia starts as a satrapy of the Flag of Antigonid Kingdom Antigonid Kingdom. Satrapies are notoriously independent minded and troublesome, however, and events will periodically require interactions to keep satraps happy.


Colonies typically represent subjects descended from the mother nation and have a loose, largely mercantile relationship with their overlord. Like tributaries, they neither provide manpower nor can be called into wars, but importantly each colony also provides a boost to the Commerce value.png commerce income of the overlord that usually far outstrips their direct tribute, and so can be highly advantageous to establish. Colonies can mostly only be created through certain tasks in the Flag of Carthage Carthaginian mission trees, though it is also possible for Flag of Athens Athens to become a colony of the Flag of Antigonid Kingdom Antigonid Kingdom if it finishes the loyalist path of its unique Athens in Chains national mission tree.

Mercenary state[edit]

A mercenary state is a particular type of client state that has been created by granting control of a city to a mercenary company, much like the historical 20px Mamertine Republic. As well as fighting alongside their overlord, each mercenary state will also Mercenary maintenance.png reduce the overlord's costs when hiring other mercenary companies. As well, if the overlord is a monarchy with the Enact law cost modifier.png Mercenary Contract Law enacted, the overlord can use Elect New Leader Character Interaction to replace their current leader with that of the mercenary state at the cost of some Stability.png stability, much like Agathokles himself once did. Mercenary states can only be created through the unique Flag of Syracusae Syracusae Create Mercenary State action, which represents the rich mercenary-using traditions of the Siceliotes.

Acquiring subjects[edit]

There are many ways to acquire new subjects over the course of the game:

  • Waging war and defeating a country will allow for Become subject.png forcing vassalization of existing states in a peace deal. A country can be vassalized if its Country capital.png capital is occupied in a war, with a smaller Warscore cost.png warscore cost and halved Aggressive expansion.png aggressive expansion compared to directly annexing the country. Defeated countries can be forced into any subject type that they and their future overlord fulfill the potential for, with all subject types being equivalent in terms of warscore cost and aggressive expansion gain. Like all other peace deal demands forcing vassalization is not possible if the warscore cost exceeds 100, e.g. if the realm is currently too large. Both independent nations and countries that are already subjects of another country can be subjugated this way.
  • A more diplomatically inclined nation can offer vassalization through various diplomatic influence actions. This requires that the potential conditions are met and that the target country have at least Opinion improvement active.png 100 opinion of the potential overlord, but is generally unlikely to be accepted unless the target is much weaker than, and has a very high opinion of the potential overlord. Targets are more likely to accept becoming certain subject types (such as tribal vassal or tributary status) over others (including feudatory and client status).
  • Countries can use the Demand Subject Transfer diplomatic action to peacefully take existing subject states of other nations if they are disloyal, and the target has at least 80 opinion of their potential new overlord. As with offering vassalization, military strength and the target's opinion of their potential new overlord are important.
  • The Release subject.png Release Subject action in the Nation overview screen will allow you to release a new client state out of any non-capital province. This country will be dynamically created and take on the name, culture, and religion of its capital territory.
    • Flag of Syracusae Syracusae has a special Create mercenary state.png Create Mercenary State action that instead allows releasing a mercenary state out of any non-capital city. This is the only way to create new mercenary state subjects.
  • Many events and especially missions also offer opportunities to get new subjects, both from releasing new countries out of currently owned territory (such as the many colonies and feudatories available in the Flag of Carthage Carthaginian mission trees) or from vassalizing existing countries (such as in the Italic League mission/event chain of the Flag of Rome Roman mission tree). This is the only way to create new colonies.

Subject loyalty[edit]

Each subject has a Subject loyalty.png subject loyalty value towards its overlord, visible in the diplomacy screen. This value modifies how much tribute is actually sent to the overlord and whether or not they will support and join rebellions and civil wars against the overlord.

Subject loyalty is a value between 0 and 100, where 100 signifies total loyalty.

If a subject's loyalty drops below 33, it will become disloyal, with the following effects:

  • The tribute paid to the overlord is reduced, scaling to 50% at Subject loyalty.png 0 loyalty
  • If a Civil war.png civil war happens and a subject is disloyal, it will join the revolting side.
  • A disloyal subject will never accept an offensive call to arms, and will not act in a defensive war except to defend its own territories.

Subject loyalty has a base of +10 and is determined by the total of the Subject loyalty.png loyalty of subject states modifier of the overlord and the Loyalty to overlord.png loyalty to overlord modifier of the subject. These are affected by many factors, with the most important being the subject's Opinion improvement active.png opinion of the overlord, the Land combat.png relative size of its army, and the current Aggressive expansion.png aggressive expansion of the overlord. Enact law cost modifier.png Laws, diplomatic stances, national ideas, Invention.png inventions, Military tradition.png military traditions, and many event/mission modifiers can also affect subject loyalty.

Converting subject types[edit]

The subject type of a particular vassal is typically fixed, but can be changed under certain circumstances.

Tribal vassals will be automatically converted into tributaries upon reforming from a tribe to a republic or monarchy through the [ROOT.GetCountry.GetName] and the [SCOPE.sCountry('overlord_country').GetAdjective] Treaty event. As tribal vassals have a bonus to Civilization.png maximum civilization value and growth, this will typically not take as long as tribes would normally reform.

Tributaries can request closer relations with their overlord and offer to become a client state through the [SCOPE.sCountry('tributary_more').GetAdjective] Gratitude event, which requires that the tributary to not have a Truce.png truce with the overlord, not be at War.png war, and to have at least Subject loyalty.png 85 loyalty, and can only trigger once per country. As client states can be called to war and integrated this can be highly beneficial to the overlord if it is seeking to expand in the area and has enough Diplomatic relations.png relationship slots, and means that it is possible to eventually integrate tributaries (and tribal vassals) as long as they can be made loyal enough to make the client state request.

The type of a subject can also be changed indirectly by first releasing it and then diplomatically re-vassalizing or forcibly subjugating in a War.png war, but this is still subject to the requirements of each subject type (i.e. cannot be used to get new colonies or mercenary states) and can take a few years given the need to wait for the Truce.png to expire. It is mostly useful for converting a tributary into a client state, if it is too difficult to increase its loyalty.

Integrating vassals[edit]

Only the more closely associated subject types - as a rule, those that can be called to war - can be Integrating integrated, including feudatories, satrapies and client states. Other subject types, including tributaries and tribal vassals, cannot be integrated or annexed without first breaking or changing the existing subject relationship.

Starting integration requires that the vassal has at least Opinion improvement active.png 190 opinion with its overlord. The cost of integration is equal to its Population.png population and is always at least 10. Integration progresses by a base of +0.25 each month and is affected by the Integrate speed.png integration speed modifier, some of the more important sources of which are listed below:

Integration can take anywhere from a few months for a small city state to many decades (or more) for a large, populous client state. In some situations, it may even be faster to release the subject, allow the Truce.png truce to expire while fabricating Fabricate claim cost modifier.png claims, and then annex the former subject through War.png war.