Infrastructure
Territories can be upgraded with a variety of infrastructure to improve the output and
happiness of their pops, as well as its accessibility and defensibility, at the cost of
gold. Investing in infrastructure can significantly improve a country's
income,
manpower,
research, and more, and is generally most effective in more highly populated territories.
Contents
Buildings[edit]
A wide variety of different buildings can be built in territories to give a wide variety of local modifiers, such as improving pop output and
happiness, adjusting the ratio of pop classes, driving
assimilation and
conversion, increasing the local
population capacity, adding
fortifications to the area, building
port facilities for ships, and more. The buildings available depend on the territory's rank, with different sets available to
settlements and
cities/
metropolises; some of the
settlement buildings are also restricted based on the trade good that the territory produces.
Every building has an associated gold cost and
build time, which are modified by the
build cost and
build time modifiers, respectively. Each territory can only build one building at a time, though it is possible to make a queue of buildings to construct. Once it is built, buildings do not cost any maintenance or upkeep. Any building in any owned territory can be torn down instantly at any time, which returns 1/4th of the its current
build cost to the treasury (also affected by the
build cost modifier), regardless of when or by whom the building was built. Some events and mission results may automatically construct a building in a territory.
All
Building | Province modifiers | ![]() |
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Notes | |
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Fortress | 150 | 720 days | Adds ![]() See | |
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Port | 150 | 180 days | Can only be built on ![]() Adds |
City/Metropolis only
Settlement Only
Building slots[edit]
The number of buildings that can be built in any particular territory is limited by that territory's number of building slots. Each building takes up 1 slot, including those under construction, and no buildings can be built in a territory that has filled up all its slots. Territories that have more buildings than their number of permitted slots - for instance, after losing population during a sack - will lose any buildings over the limit.
Wonders also take up a building slot, and require at least one empty building slot to begin construction.
Settlements normally only have 1 building slot (though settlement buildings are in general stronger than other buildings), which can be increased by the
global settlement building slots modifier to a maximum of 2 by researching the
Rural Planning
Civic invention (though each settlement building will still have its territory cap of one). Building slots mostly become relevant when settlements are upgraded to
cities, which gives a base of 2 extra building slots and an additional 1 for every
10 pops in the city. If a city is further upgraded to a
metropolis the base number of building slots is increased to 4. Other important sources of building slots in
cities and
metropolises, given by the
local building slots and
global city building slots modifier, include:
- +1 for the
country capital
- +1 for
holy sites
- +1 for all
cities with a
tier 3 wonder with the
Engineering effect
- +2 for all
cities with a
tier 4 wonder with the
Engineering effect
- +2 for all
cities with the
Urban Planning
Civic invention
- +1 for all
cities with the
Legacy of the Builders military tradition (Levantine and Arabian traditions)
- +1 for each
Make Religious Endowments religious province investment
Great wonders[edit]
- Main article: Great wonders
Great wonders are special buildings that can be constructed in territories and give powerful bonuses to their local province or owner. Unlike standard buildings, wonders can be customized with various designs, materials, and effects, and are a significant investment that only the large and wealthy empires will be able to afford. As the centerpiece and defining feature of the local area, each territory can normally only support one great wonder, though certain wonders that are built by event can coexist with each other in the same territory. Uniquely, wonders usually give strong nation-wide effects that grow over time as the wonder's fame and prestige increases.
At the start of the game, there are a number of ancient wonders scattered all over the map, from the Temple of Jupiter Optimus Maximus in Rome to the Great Pyramids of Giza and the University of Taxila. Building additional wonders requires the Heirs of Alexander DLC.
Roads[edit]
Roads can be built by
armies to connect two adjacent territories at the cost of
gold, reducing the
movement cost by 50% and effectively doubling the army movement speed between them, making them highly desirable for larger empires that would benefit from being able to move armies between their provinces more quickly. In addition to the army movement bonuses, connecting a territory to the road network also gives a minor boost to development, trade, and pop mobility, making them useful to build in highly populated developed territories as well as connecting frontier areas. Roads also appear graphically on the map as the network is built and extended, generally being most prominent on the terrain mapmode; if a road is built over a river, a bridge will appear. Unlike with buildings, roads are not associated with individual territories, but instead with pairs of adjacent territories (including possibly those connected over a strait); it is therefore possible (and common) for a territory to be a part of multiple different road segments. For every road connecting a territory to one of its adjacent territories, a territory will get the following stackable modifiers:
+0.001% Monthly Civilization Change
+2.5% Pop Conversion Speed
+2.5% Pop Assimilation Speed
+2.5% Pop Promotion Speed
+1% Pop Demotion Speed
+0.05 Migration Attraction
+0.1 Pop Migration Speed
+5% Local Base Trade Routes Modifier
There are two ways to build roads - a special, cheaper method for countries with access to Italic tradition groups, and more generic one that is available to all countries. Once a road is built, it cannot be removed or destroyed, even if the territories it connects are completely depopulated.
Regular roads[edit]
Most countries need to reach at least Level 5 of civic advances to begin building roads.
Roads can be built using the Build Road unit ability toggle, which can be activated if all of the following conditions are met:
- The unit is an
army
- The army has at least
10 cohorts
- The army is not in combat, moving, or exiled
- The army is in a territory that is owned by the current country, or by one of its
subjects
- The army either has no commander, or its commander is loyal (i.e. has at least
34 loyalty)
Any type of army, even levies and
mercenaries, can build roads, if they meet all of the requirements.
When the build road toggle is on, road construction will begin when the unit moves from one territory to another, as long as both territories either owned and controlled by the army's owner or one of their
subjects, or are uncolonized (including uninhabitable territories, though not impassable terrain). When the army arrives in that other territory, if the two territories do not already have a road between them, the road will be instantly built at a base cost of
50 gold. This cost is affected by the
build roads cost modifier, given only by the
Civic inventions
Gromatici (
-25%) and
De Architectura (
-15%). If the army has at least
1 engineer cohort, the cost of building a road is instead lowered to to
10 gold (not affected by any modifiers).
While building roads, the following modifiers are applied to the army:
The toggle will be turned off if the army becomes ineligible to build roads, or if the army finishes moving to a new territory without a road on the traversed connection and the country does not have enough money to build a road.
Military roads[edit]
If a country has access to Roman traditions (in the Italic traditions group), adopting the Roman Roads tradition will give access to the special
Build Military Road toggle, even if it does not currently meet the technology requirements for building roads normally.
Building military roads is largely the same as building regular roads, with the main differences that the road-building army can be smaller, requiring only
5 cohorts, but must be a
legion, and that each road costs only
25 gold per territory connection. However, note that the cost is not affected by the
build roads cost modifier. As with normal road building, the cost is lowered to to
10 gold (also not affected by any modifiers) if the army has at least
1 engineer cohort.
As well, a reduced set of modifiers is applied to the road-building army, without the increased maintenance cost or morale penalty:
Forts[edit]
- See also: Siege
Forts can be built in territories to block the advance of enemy armies and protect important cities and strategic points from being easily captured. The size of a fort is determined by its
fort level, with 1 as the minimum and 0 indicating the lack of a fort in the territory, and every
fortress building giving
1 fort level. Note that this means that
settlements are typically restricted to a
fort level of 1, with only
cities and
metropolises usually able to support larger forts. Each fort level gives -1 to siege progress and provides the base
garrison of 500 per fort level, adjusted by the
garrison size modifier. An besieging army needs to be at least 4 times as large as the garrison to begin a siege, and when a fortress falls (or a new fort level is built), its
garrison will need to be replenished at a rate of 10% of the max garrison per month. Forts with a high fort level will therefore need both a large commitment of forces and a significant amount of waiting to successfully take, and can be a potent defensive measure at important chokepoints.
In addition to the opportunity cost of taking up a building slot, every fort, except for the first
capital fort, also costs a base of
0.60 gold in maintenance each month, adjusted by the
fort maintenance modifier.
Each fort in an owned territory also contributes to the total number of fort points in the province, with the first fort in a territory giving 3 fort points, and all subsequent ones 1. Every territory in the province gets -0.25 unrest for every fort point in the province; this makes spread forts out over a number of territories much more efficient at suppressing unrest than concentrating them in a single territory. However, each province also has a
fort infrastructure capacity that controls how many forts points a province can have before incurring additional maintenance costs. Each province has a base fort capacity of 5, which can be increased by several
military traditions, some
inventions, and as a
wonder effect. This means that, without any bonuses to fort capacity, each province can only support 1 territory with a fort (for each country that owns territories inside the province) without going over the limit.
The fort infrastructure capacity does not serve as a hard limit, but instead applies a +25% fort maintenance modifier to every owned fort in the province for every point over the province's fort capacity, which can very quickly add up for highly fortified provinces. Fortifications are therefore quite costly, particularly for smaller countries, and it is often a good idea to remove extraneous forts that no longer serve any meaningful defensive and unrest-suppressing purpose if the maintenance costs are becoming an issue.
One of the other main effects of a fort is that it prevents enemy armies from being able to occupy the territory after the base occupation time of 15 days, but instead requires the attacker to successfully siege or assault the
fort before the territory can be occupied. In addition,
forts exert an zone of control over the adjacent territories, restricting enemy movement and controlling nearby territories. An
army that enters a hostile zone of control will not be able to progress further, and must instead either proceed to the
fort and besiege it or return to the territory they came from - in this way, a line of
forts one or two territories apart can completely block an enemy army from progressing past it, and can be useful along contested frontiers or to protect valuable core areas. As well, any hostile territory within a zone of control of a
fort that is not being besieged will have occupation progress as though an army was occupying it, unless an army on the same side as the current controller is currently in the territory; if a territory lies in the zones of control of multiple hostile forts, it will continually switch occupation every several days between each side. Territories within a friendly zone of control will also not lose
civilization value when occupied by
barbarians, making them useful to build near barbarian strongholds. Zone of controls are fully active for not only owned and controlled forts within the country, but also controlled forts within enemy nations, making it possible for a counteroffensive into previously occupied territory to be blocked by a country's own occupied forts.
Border forts[edit]
- See also: Colonization
A country that has adopted the Castra military tradition from the Italic tribe traditions tree can have an army build a
border fort in an owned frontier or neighbouring uncolonized territory. An army can do this action if it meets all the following conditions:
- The unit is an
army
- The army has a loyal commander (defined as
34 loyalty or higher).
- The army is not in combat, moving, sieging, or exiled.
- The army has at least
5 cohorts, including at least one that is not
loyal to anyone. (This requirement implictly means that
mercenaries cannot be used)
- The territory the army is in:
When the ability is activated, the country loses 3000 manpower and builds a
fortress in the territory. The country then gains ownership of the province if it was previously uncolonized, in which case the territory will also gain a
freeman pop of the primary culture and religion. Finally, one random cohort becomes
loyal to the commander, unless the general is the ruler of a non-republic, in which case the country gains
1 tyranny instead. This ability can notably be used to colonize territories even if there is no neighbouring territory with a dominant integrated culture and state religion.
Ports[edit]
Ports are buildings that can be built in any
coastal territories, as well as certain inland territories on
major rivers (those that begin the game with a
port). They allow
ships to dock (including quickly embarking and disembarking troops), be built, repair, and supply, and are important for any nation that seeks to maintain a significant navy. The number of ports in a territory is the territory's port level, which in addition to the effects from the port buildings themselves also determines what types of ships it can build and repair: the light
liburnians and
triremes only require a level 1 port, the medium
tetreres and
hexeres require at least level 3 ports, while the very heavy
octeres and
mega-polyremes can only be built and repaired at ports that are at least level 5.
In addition to effects from the building itself, every coastal territory with at least one port gets the following modifiers:
For each territory in a province that has at least one port, the province also gets the following modifier:
Note that neither of these effects stack if territory has more than one port.
Pirate havens[edit]
Certain ports are home to pirate havens where groups of pirates are based from. These pirate havens are present in certain ports at the beginning of the game, and in addition to giving an economic boost of
+20% Local Tax and
+0.01% Local Population Growth to their territory they host pirate fleets, always composed of all light ships, which can rented out as naval mercenaries at times of war. When not being hired pirate fleets will eventually grow restless and go on raids, at which point the fleet while become hostile to all other navies and travel to nearby unfortified ports to plunder them, giving
-25% Local Tax and
+10% Demotion Speed to the plundered territories.
If pirates grow to be too much of a problem, their havens can be destroyed using the Root Out Pirates army ability on any controlled territory once the anti-pirate law has been passed, including those belonging to other countries that have been occupied in a
war. This will remove the modifier (including its beneficial modifiers) and destroy the associated pirate fleet, even if it is currently out on a raid. Alternatively, pirates can be actively encouraged by passing the pro-pirate law, which will create a new
pirate haven in one of the country's ports to increase its prosperity and provide more available naval mercenaries at the expense of the nearby coasts.
Destroying all ports in a pirate haven will also force any local pirate/mercenary fleets to disband, though this will not remove the pirate haven itself. If the port is ever rebuilt, the pirate fleet will eventually reappear.
Concepts | Buildings and Infrastructure • Colonization • Tax • Trade and Commerce • Trade goods • Population |
Domestic policy | State • Attributes • Characters • Civil war • Culture • Government • Heritages • Laws • National ideas • Position • Rebellion • Religion • Technology |
Economic policy | Buildings and Infrastructure • Economy • Food • Great wonders • Population • Trade • Trade goods |
Provinces | Region • Province • Territories • Colonization • Holding |
Military | Military traditions • Army • Distinction • Land units • Land warfare • Siege • Naval warfare |
Foreign policy | Treaties • Warfare • Casus belli • Claim • Diplomacy • Subject nations • Barbarians |
Script | Events • Decisions • Missions |
Other | Achievements • Antagonist • Difficulty |