Subject nations

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

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

• All subject types pay some sort of resource to their overlord, with the exact type and amount depending on the subject type.
• Other than for trade and allowing military access, a subject can never enter into diplomatic agreements with other countries.
• 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 military access to each other's territory.
• Subjects always have military access to the territory of other subjects of the same overlord.
• A subject can always leave a subject relationship by declaring war on their overlord. They cannot declare war on any other country.
• An overlord can release any of its subjects at any time, as long as there is not a truce. Breaking the relationship does not give a truce, and so the former subject can be attacked immediately once the diplomat has returned.
• Overlords will always be called to 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 (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

Legend:

• Requirements: These conditions must be true in order to diplomatically request making another country a subject of this type, or enforcing this subject type in a war. Note that this only applies when creating a subject; a pre-existing subject that fails to meet the requirements for its type will not become independent or (in general) convert to another subject type.
• Payment: The subject makes this payment to the overlord on a monthly basis.
• Dip. slot: Whether a subject of this type counts as a diplomatic relation towards 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 exports: Whether the subject is limited to only being able to export to its overlord (imports are not affected).
• 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	Dip. slot	Join wars	Integrate	Break	Limit exports	Effects
Tributary	None	15% of income						None
Feudatory	Overlord is not tribal Overlord has at least 20 territories Subject has no more than 10 territories Subject and overlord are in the same culture group	15% of monthly manpower gain						Subject: −10% Army Maintenance Cost −4% National Citizen Happiness
Tribal vassal	Subject is tribal, and the overlord is not Overlord's capital civilization value is higher than in the subject's capital Overlord has fewer than 10 tribal vassals	15% of monthly manpower gain						Overlord: +4% National tribesmen happiness Subject: +10% Country civilization level +0.01% Monthly civilization change
Satrapy	Subject has access to Persian traditions and more than 40 territories Overlord is a monarchy with at least 150 territories	25% of income						Overlord: +2% Monthly legitimacy
Client state	Neither subject nor overlord is tribal Subject has fewer than 150 territories	25% of income						Subject: −5% Ruler popularity gain +10% National commerce income Can only export to overlord.
Colony	Only by event/mission	15% of income						Overlord: +5% National commerce income Subject: +10% National commerce income +25 Loyalty to overlord
Mercenary State	Magna Graecia is enabled One of the following is true: Is or started as Syracusae Has adopted the Satellite Status Oratory invention Only by releasing a city through the Create Mercenary State action	10% of income						Overlord: -3% Mercenary Army Maintenance Subject: +12.5% National Manpower -20% Legion Maintenance Cost
League City	Heirs of Alexander is enabled Has adopted the Coloniae Civic invention Only by releasing a city through the Create League City action	10% of income						Subject: +0.10% National Population Growth +2 Capital Import Routes +5% Country Civilization Level -4 Slaves needed for Surplus

Tributary

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, with the only risk being that the former overlord will get a 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 35 loyalty
• Has more army cohorts than the overlord
• Has less than 50 loyalty, owns more than 3 territories, and borders the overlord

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

Feudatory

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 to their overlord and are expected to take part in their wars. As the only subject type that can be called to war but does not cost a diplomatic relations slot, feudatories are one of the strongest subject types and building a large network of feudatories can substantially increase a nation's strength, but this is limited as feudatories can normally only be made of countries in the same culture group. Historical examples are the Roman Socii, the Punic cities of North Africa under Carthage, or the city leagues in Aegean under the Antigonids.

If a country has the Proportional Agreements Oratory invention, small countries (with less than 12 territories) that are guaranteed may occasionally request feudatory status, which can be an important method of diplomatic expansion.

Tribal vassal

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 and the growth of it in all their territories. The tribal state in turn pays with its manpower to the overlord who, will also promise to protect them. Historical subjects of this type would be the Numidian kingdoms subject to Carthage and various Roman clients on the later imperial border. When a vassal tribe adopts a civilized form of government, it will become a tributary.

Client state

Client states are in some ways more tightly integrated with their overlord, but unlike the feudatories they are not necessarily of the same culture group and they do not enjoy a privileged status in the same way, paying a large part of their income instead of providing 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, converted from loyal tributaries through an occasional event, or released from the country's currently owned provinces in the Nation Overview.

Satrapy

Satrapies are a special type of subject that is only available if the junior party has access to the Persian traditions military tradition tree. The fundamental unit of organization in Persia since the time of the 20px Median and 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 somewhat comparable to a client state. As having powerful satraps is an expectation in the east a few of them will also help with maintaining the legitimacy for their overlord kingdoms. Satrapies are notoriously independent minded and troublesome, however, and events will periodically require interactions to keep satraps happy.

Since the conquest of the Achaemenid Empire almost all the old Persian satrapies are now ruled by Macedonians, with satrapies at the start date including Bactria, Parthia, and Arachosia under the Seleukid Empire and Cappadocia under the Antigonid Kingdom; Sardis and Phrygia can also be released as satrapies of Thrace if the Antigonid Kingdom collapses. The Hellenistic Empire can also establish a number of its own unique satrapies through the associated Hellenistic Empire mission tree.

Colony

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 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 Carthaginian mission trees, though it is also possible for Athens to become a colony of the Antigonid Kingdom if it finishes the loyalist path of its unique Athens in Chains national mission tree.

Mercenary state

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 reduce the overlord's costs when hiring other mercenary companies, and if the overlord is a monarchy with the Mercenary Contract Law enacted, the overlord can use the Elect New Leader Character Interaction to replace their current leader with that of the mercenary state at the cost of some stability, much like Agathokles himself once did.

Mercenary states can generally only be created by releasing an owned city through the Create Mercenary State territory action at the cost of 50 political power, available from the start of the game to Syracusae (representing the rich mercenary-using traditions of the Siceliotes) or to any country that has adopted the Satellite Status Oratory invention. The 20px Mamertine Republic, when released, will also be a mercenary state.

League city

A league city is a city that has been granted substantial autonomy and, like colonies, have a loose, largely mercantile relationship with their overlord. League cities are generally focused on trade and production, with powerful bonuses to capital import routes and especially slaves needed for surplus trade good production. This can make them useful as a trade partner to import excess goods from the mother country, as well as producing surpluses of valuable trade goods that can then be exported to the overlord.

League cities can only be created by releasing an owned city through the Create League City territory action at the cost of 50 political power, available to any country that has adopted the Coloniae Civic invention.

Acquiring subjects

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

• Waging war and defeating a country will allow for forcing vassalization of existing states in a peace deal. A country can be vassalized if its capital is occupied in a war, with a smaller warscore cost and halved 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 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 action in the Administration tab of the Nation overview screen allows a country to release a new client state out of any non-capital province, if there are diplomatic relation slots available. This country will be dynamically created and take on the name, culture, and religion of its capital territory.
  • The Create Mercenary State territory action in the Tactical tab, available to Syracusae and countries that have adopted the Satellite Status Oratory invention, instead allows releasing a mercenary state out of any non-capital city, if there are diplomatic relation slots available. This is the only way in general to create new mercenary state subjects, and requires the Magna Graecia DLC.
  • The Create League City territory action in the Tactical tab, available to countries that have adopted the Coloniae Civic invention, instead allows releasing a league city out of any non-capital city. This is the only way to create new league city subjects, and requires the Heirs of Alexander DLC.
• If a pretender that the country has supported using the Support Pretender interaction wins a civil war, they can be forced to become a client king if their country is a lower rank than their sponsor.
• If the Proportional Agreements Oratory invention has been adopted, countries in a larger power's Sphere of Influence - those that are guaranteed and own less than 12 territories - will occasionally offer to become a feudatory of their protector.
• 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 Carthaginian mission trees) or from vassalizing existing countries (such as in the Italic League mission/event chain of the Roman mission tree). This is the only way to create new colonies.

Subject loyalty

Each subject has a 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:

• If a 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 loyalty of subject states modifier of the overlord and the loyalty to overlord modifier of the subject. These are affected by many factors, with the most important being the subject's opinion of the overlord, the relative size of its army, and the current aggressive expansion of the overlord. Laws, diplomatic stances, national ideas, inventions, military traditions, wonders, and many event/mission modifiers can also affect subject loyalty.

Converting subject types

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 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 with the overlord, not be at war, and to have at least 60 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 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, 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 to expire. It is mostly useful for converting a tributary into a client state, if it is too difficult to increase its loyalty.

As with most mechanics, there are also certain country-specific events and mission tasks that can convert subjects between different types.

Integrating vassals

Only the more closely associated subject types - as a rule, those that can be called to war - can be 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 190 opinion with its overlord. The cost of integration is equal to its 0.75 times its population and is always at least 10. Integration progresses by a base of +0.25 each month and is affected by the integration speed modifier, some of the more important sources of which are listed below:

• +0.05 per point of diplomatic reputation
• +0.25 with the Domineering diplomatic stance
• +0.05 for each tier of the Diplomatic Traditions great wonder effect
• +0.10/+0.20/+0.30/+0.50 depending on the tier for great wonders with the Diplomatic Expansion effect
• +0.30 with the monarchy King of Kings Law
• +0.05 per country rank, up to +0.25 for great powers
• +0.10 with Roman heritage

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 fabricate claims on a subject, then release it and declare war to annex its territory, at the cost of losing all trade routes.

Mechanics