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Dev Diary #8 - Cities and Expansion

Hello everyone!

My name is Sam Minh Ly, a designer at Triumph in charge of the economy of Age of Wonders 4. In this dev diary I would like to talk about the economy and city development. Shoutouts to Glenn and Lennart who did a lot of work to design the systems of the economy in Age of Wonders 4.

Spoiler: There is a small teaser in the end of this Dev Diary, so make sure to read it till the very end!

Cities are at the core of your empire. They will use the surrounding land to provide you with the resources to raise armies, research Tomes of Magic and provide the mana to fuel your spells. They will also prove to be a good way to exert your control over the world. Cities lay claim to the surrounding area, making it difficult for enemies to come close without diplomatic penalties. And during war, cities are bastions that require a serious effort to breach.

City Income


Let’s start off by explaining all the resources that cities produce. 

  • Food is required to make a city grow in population. 

  • Production is used to build city structures, which in turn provide resources or other benefits.

  • Draft is used to recruit units for your armies.

  • Gold is mainly used to build city structures and recruit units, but it can also be used in other manners, such as diplomacy.

  • Mana is used to cast spells and summon magical units.

  • Knowledge is used to research new skills from your tomes, which unlock new spells, units and more.

  • Imperium is used to further your empire as a whole. Its main use is for unlocking Empire Skills and acquiring new cities, but it can also be used to grow cities and in diplomacy.

Food, Production and Draft are all used in the same city that produced that resource, while Gold, Mana, Knowledge and Imperium are added to your global resource pool and can be used anywhere.

City Structures


The primary way to gain more resources is by building city structures. There are four buildings for every resource and a well planned city can build all of these in a single city except for the Tier 4 structures, which are mutually exclusive. All structures have a gold and production cost, the latter of which determines how long it takes for your city to build that structure. You will see that all these structures have a boost requirement. We will cover that a little further in this dev diary.


In this diagram you can see a few different types of city structures. The Town Halls unlock new structures and special province improvements, which will also be covered later in this dev diary. A city always starts with the 1st Town Hall, providing a bit of a background income to get you started.

To the right of the town halls are the fortification structures. They provide Fortification Health, which determines how long it takes for enemies to siege the city before they can attack it. Many of them also provide an additional benefit during the actual battle, giving the defender an advantage in the fight.

On the left you can see the city stability structures. A city’s stability goes down as the town grows in size. You want to avoid your city to have a negative city stability.


Finally we have the Wizard Tower. Which is exclusively built in your capital, the Throne City. It provides empire wide benefits for your Godir. It is also the main way you can increase your Imperium income.

Building Queues


Much like in previous Age of Wonder games, your cities can construct buildings which provide passive income each turn. Unlike previous games, the queue to build structures and units has been split in two, allowing you to construct structures and recruit units at the same time. This is paired with the new Draft resource, which is exclusively used for recruiting units. We made this decision so players could more easily bounce back after losing units in battle without destroying their city development progress.  

When a queue is empty, it automatically starts to produce resources at a conversion % instead. Production is converted into Gold and Draft into Food.

City Domain


Cities project a sphere of influence around the city called their domain. This domain extracts resources and ensures rival players can’t just enter it without consequences (more about diplomacy in a future dev diary!) 

In Age of Wonders 3 and prior, this domain was a hexagon-shape that grew equally in all directions out from the city. This allowed it to exploit the natural resources of nearby resource nodes but gave the player no control. In Age of Wonders: Planetfall this was changed to a sector system, which resulted in player control over growth and more natural shapes that follow the environment. But these choice moments were few and far between and it was hard for many players to comprehend the impact of these choices. 

Age of Wonders 4 uses a new province and expansion system. Provinces also follow the natural features of the world. They are smaller than sectors and unlike Planetfall you will gain a new province every time you gain a new population. Cities can easily get up to 15 population and 15 provinces,  making your cities grow more organically in byte-sized chunks. This allows you to “steer” their expansion towards high value resources or to cut-off bottlenecks with your territory.  

Province Improvements


Whenever you annex a new province you can immediately choose what type of province improvement will be built here.

The choice of improvements depends on what features that province has.

  • Farms can be built on grasslands and provide 5 Food.

  • Quarries can be built on rocky terrain and cliffs and provide 5 Production.

  • Foresters can be built in forests and provide 2 Food and 3 Production.

  • Mines can be built on provinces with Iron Deposits or a Gold Vein and provide 5 gold.

  • Conduits and Research Posts can be built on provinces with a Mana Node or Magic Material. The Conduit provides 5 mana and the Research Post 5 Knowledge.

  • Fisheries can be built on coastal provinces or in underground lakes and provide 5 Food.

  • Huts can be built when trying to settle in inhospitable regions, such as a frozen tundra or a scorching desert. They provide 3 Food and do not count as farms, which is important for other economic systems that we will cover further down. Choosing an adaptation allows you to build farms in those regions instead.

City Structure Boosts


For those that want to optimize their city development, we have the Boosting system which ties building city structures in your city to choosing new province improvements in your domain. Almost every structure has a boosting requirement in the form of specific province improvements. For example, the Library requires 1 Forester in a City’s domain to become boosted. If it is, the structure will require 30% less Gold and Production to build, making the boosts worthwhile to chase after and plan for when developing your cities and choosing province improvements.  Of course higher tier structures require multiple Province improvements to be present.


Building structures often unlocks more structures that are more expensive, but also provide more resources. Higher tier structures also require specific province improvements to be present in your domain. So you will need to make sure that the environment around your city can support a variety of province improvements and think about which improvements to build

Special Province Improvements

As you progress through the game and unlock Tomes, you will acquire Special Province Improvements. These use the city construction queue, are often quite expensive and need to be built on top of any existing province improvement. But they provide more income than the basic province improvements, especially because they come with extra bonus income that is dependent on the type of adjacent province improvements, adding another dimension to planning your city.

Here are a few examples of what effects these Special Improvements can have:

The Mob Camp is an early game Special Province Improvement from the Tome of the Horde and fits with the Tome being about amassing an army of cheap units. It also allows you to set a province as a Unit deployment location, allowing your units to be recruited at the edge of your domain.


The Frostspire is acquired from the Tome of the Cold Dark. It benefits from the terraforming effects you get from the Tome and provides friendly visiting armies a buff for their next combat.


The Sanctuary specializes in another angle and instead provides defensive bonuses to your domain. Preventing enemies from pillaging and casting spells in the domain.


Capstone City Structures: Guilds


At the peak of your city's development are the Guilds, which are capstone buildings that provide a huge amount of income based on the number of province improvements of a certain type. For example the Mages Guild, the final mana structure that unlocks if you built all three mana structures before it. It provides 10 mana per Conduit in the domain! But only a single guild can be built per city. So you will have to choose what you want the city to specialize in. Of course this is dependent on the environment, so keep an eye out to the surroundings of your cities.

Faction Differentiation 

There are 6 cultures in Age of Wonders 4. Each with their own specializations in combat and in their economy. Each culture has multiple global bonuses that are unique to them which change how you play. For example, the Dark culture disables the negative effects from low City Stability, the High culture gains global bonuses based on whether you have a good, neutral or evil alignment. Aside from that, every culture gets unique units, Hero Skills, unique city structures and a unique Special province Improvement.

Let’s have a look at what the Industrious culture gets that other cultures don’t. Their unique structure after building a Tier 3 Town Hall is the Bastion’s Barricade. Which exemplifies Industrious’ aspect of fortification perfectly. It provides 20 Fortification Health other cultures can never get and the two Bastions are the strongest units the Industrious culture has, Tier 3 Shield units with immensely high physical defense.


The Tier 1 and Tier 2 Food structures of the Industrious culture are replaced. Instead they gain the Workers Farmstead and the Grand Mill. Which provide less food than their normal counterparts but they also provide Production, which they normally don’t.


Their Special Province Improvement is the Builder’s Quarters. Which is a quarry that provides more production for each adjacent quarry. As you can see these bonuses can get really high if you get the right spot for them.


Now with all that extra production you can either continue to build high tier structures or you can use the Produce Merchandise option every city has. It normally converts 25% of a city's unused production into Gold. And while that is already good for the Industrious culture as their Production can become really high, they go even further. If you build their Tier 4 Town Hall, it not only provides the bonuses any Tier 4 Town Hall provides, but it also increases your Produce Merchandise conversion rate from 25% to 35%!


To wrap up this example I will give you an idea of what kind of synergies you can use to optimize your economy. As you might have seen in the Builder’s Quarters screenshot, there is a +2 gold bonus coming from something called Great Builders. This is one of the Society Traits you can choose when creating your faction. It itself combo’s really well with the Empire Skill Specialist Districts. Now your Special Province Improvements cost less Production to build and provide gold. The Materium tomes have many Special Province Improvements, some of which count as quarries, which will maximize the benefits from all these synergies.


City Cap and Automation 

Growing your empire by acquiring new cities is vital to growing your economy, but you cannot spam new cities indefinitely. If you over extend, you reach your City Cap. If you do so, every city in your empire will suffer a hefty -25% income penalty. This cap is meant to pace city acquisition and to stop rampant expansion. This will force you to either increase this cap via the Empire Skill Tree, or invest in your established Empire.

Another way to reduce micromanagement is the City Automation system. It allows you to set a focus (if any) and let the city grow on its own without having to choose every single province you can acquire.


For those that do want to micromanage and control their Empire in every detail, you need not worry. You can invest your Imperium into extra City Cap indefinitely, but it will cost you more Imperium each time.

Vassalization System


And for both players we also have another way to exert your control over the world, namely the vassalization system. There are many Free Cities in the world that you can vassalize. If you do so, they will provide a portion of their income to you, depending on how strong your bond with them is. Moreover, you can decide to vassalize any city you conquer. These vassals do not count towards your city cap but they do provide you with income and a safe place to return to and recover between your campaigns. You can also integrate them later if you decide you want a particular city. Or you can vassalize your own cities directly to free up a city cap slot. Via vassals you can spread your rule over the entire world without limit.


There are many layers to the development of your city, which unlock as you progress through the game. The core loop of growth and immediate province exploitation is direct and meaningful. You can choose to engage with this in a casual manner but also choose to highly optimize your economy which is a necessity in the higher difficulty levels. 

While there are other factors that influence your economy, such as the Society Traits and the Empire Skill Tree, this will do it for this dev diary. So, what do you think you will do? Plan the development of your city meticulously, go with the flow, or automate?  or will you simply take cities by force? It is up to you to decide what path to follow.

While the next diary will be dedicated to the Ancient Wonders, there is also a new stream coming up!

We will let the community pick the faction, form, and tomes for our Developers to start with, so keep an eye on the Forum as we will let you vote next Wednesday!

Stay tuned for a new dev diary next week and consider adding the game to the Wishlist!