Horreum Romanus

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Horreum Romanus

Being a store of the information we know about Imperator: Rome.

The vision for the game
The map
The resource system
Population mechanics
The economy and buildings
Country Rank
Unit Abilities
The Senate
Offices & Laws
Military Traditions
Bits & pieces
Characters pt.2
Military Traditions pt.2
Governor Policies & North African Military Traditions
Land Combat and Combat Tactics
Italy 450 AUC (304BC)
The Greek World and Greek Military Traditions
Religion, Anatolia and the Aegean
National Ideas, the Southwestern Meditteranean & Carthage
The Economy and Egypt
Pops, colonization, The Levant and Levantine & Arabic Traditions
Combat Mechanics
Trade, Diplomacy and The British Isles
Interface & Mechanics update
Mercenaries and The Arabian Peninsula
Monarchies and Persia
Navies, more Diplomacy, Bactria and Parthia
Tribal Chiefdoms and Gaul
Character Ambitions, Persian Military Traditions, the Caucasus and Black Sea
Civil Wars, Rebellions and Subject States
Tribes, Tribal Migration and Germania
Families and Scandanavia
The Alliance System and India
Diplomacy, Expansion, Foreign Realtions and The Horn of Africa
Mercenaries, Forts, Tribes, Achievements and Formable Nations
Barbarians and The Far Himalaya


Alexander. Hannibal. Caesar. These great men and dozens like them shaped the destiny of a continent. Mighty kings, clever generals and would-be gods made their mark on the ancient Mediterranean.
Around this sea, close-knit nations tested their mettle and virtue against each other in fierce combat, their cultural and political legacy now inseparable from what we understand as Western Civilization. But nothing was guaranteed. Can you change the course of history in Imperator: Rome?
Main Features
Character Management: A living world of characters with varying skills and traits that will change over time. They will lead your nation, govern your provinces and command your armies and fleets. We also introduce our new, more human-like character art.
Diverse Populations: Citizens, freemen, tribesmen and slaves - each population with its own culture and religion. Whether they fill your armies, fill your coffers or fill your colonies, keep an eye on their happiness - your success depends on their satisfaction.
Battle Tactics: Choose your approach before battle to counter the stratagems of your foes.
Military Traditions: Each culture has a unique way of waging war. Romans and Celts have different options available to them. Unlock unique bonuses, abilities and units.
Different Government Types: Manage the senate in a Republic, hold your court together in a monarchy, answer to the clans in a tribal system.
Barbarians and Rebellions: Migrating barbarians may sack or settle your best land, while disloyal governors or generals can turn against you - taking their armies with them!
Trade: Goods provide bonuses to their home province. Will you take advantage of stockpiles for local strength or trade excess goods to spread the wealth around?
Provincial Improvement: Invest in buildings, roads and defences to make your kingdom stronger and richer.

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The vision for the game - DD#1

We have often talked about how close we are with the community, but this is the first game we have made where a post from a forum-member is quoted at the top of our Game Design.

The balance between CK2 and EU4/Vic2 should remain in Rome2. Rome was a fantastic mix between CK1(characters), EU3 (diplomacy, and war) and Vic1(parties, provinces system and population dynamic) and its own feature like barbaric migration and the best civil wars in Paradox games - @Leon_Aditzu

This was such a great post describing Rome, so that when we started with Imperator, it was a natural to use.

In this game we’ve wanted to stay true to this vision, while implementing the knowledge we’ve learned in the last decade of making games with better UX and player agency, while increasing the depth and complexity enormously.

There were a few main things with the original that was really bad though, and that we have decided to remove or change.

We’re removing characters as envoys, as that was a bad mechanic, and you primarily used to get rid of people.
Omens and Religious Prestige were not very fun, and have been changed.
Trade was lots of micromanagement, this have been reworked for a more interesting and fun mechanic.

All in all, whenever possible we’ve strived to be adding more depth and complexity to the game, to make this into the ultimate GSG.

Here's a quick look of Iberia and beyond!1.thumb.png.050e07406c913c2bc979ca0789975ef7.png


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The Map - DD#2

This is arguably the biggest and most detailed map we have had made for a game ever. More is not always better though, as of which the original release of HoI3 is a great example. We have taken good care into making a game where you can have interesting situations both while playing a small state, and while playing a vast empire.

In various games before, we’ve worked with organising entities on the maps in various ways, with States being groups of provinces tracing back to Vicky1. In Imperator we’ve been designing the game from the ground up with having 2 layers of interaction. The smallest part of a map is what we call a city, which corresponds to about a province in previous games. A city holds a city (or village, or metropolis), a bunch of pops, produces a trade-goods and may have a few buildings. A Province is a group of cities all belonging to the same country. A province is usually about 10 to 12 cities, and this is the entity you interact with to control trade and assign governors to.

Let us quickly compare how Sicily have been depicted in our previous games, as this is where we’ll take a look today.

Eu2 had 2 provinces
CK2 has 5 provinces.
Eu4 has 3 provinces
HoI4 has 9 provinces

In Imperator, Sicily has 23 cities (provinces in previous games), and 4 impassable mountain range areas. Its 23 cities are divided into two provinces - East Sicily and West Sicily

This creates a much more interesting military campaign, and also more variety in your peacetime activities.2.thumb.png.dc264f385ec89b6513c84724ecab54be.png2.thumb.jpg.9f5d5ac6898137a3ab0aa43d2ddd391b.jpg

Of course, as you would expect from a game with Rome in its title, we have the entirety of Mare Nostrum covered, but there is far more of the world in the game than just that area. And with those words I’ll hand over the keys to @Arheo & @Trin Tragula , our research team!

One of the major reasons behind our choice of start date, aside from being a particularly interesting period in Roman history, is the state of the successor kingdoms in the east. We’ll go into depth about those in another development diary, however, it is worth noting that many of our decisions to include certain territories were down to their relevance within the hellenistic world, as being fascinating in their own right.

Britain made up a sizeable portion of historical Roman conquests, and played an important part in the tin trade throughout the bronze age, into the iron age. Data on pre-roman Britain is scarce, particularly for the period preceding 150 BC, and some liberties have therefore been taken regarding the extrapolation of tribal territory as known to Caesar.

The inclusion of southern Scandinavia, despite it being the epitome of all modern civilization (enough of that now - Editor), was a calculated decision. Our start date of 304 BC places us during the migration (not to be confused with the Migration Period, which occurred as of the 4th century AD) of the original Germanic tribes from modern-day Scandinavia, into northern and central Germany. The displacement of the native inhabitants (about whom very little is known), and latterly some of the celtic tribes, occurred over the course of the next several hundred years. As with Britain, very little concrete data exists on the exact nature of the locations and names of tribal groupings towards the beginning of this period.

The recorded history of the Ethiopian region extends back far further than our timeline, however, none of the contemporary sources we were able to discover, were particularly detailed regarding location data or political situation. Even now, structures built by the D’mt kingdom around 700 BC still stand, a testament to the advanced civilizations out of which the contemporaries of our start date grew. The Nile has always been the lifeblood of north-eastern africa, and we felt it was worthwhile including as much of it as possible.

The inclusion of the Indian subcontinent is something we considered as vitally necessary to complete the world that was relevant to the Hellenistic era. A state of conflict had already existed for some time between the recently established Mauryan Empire, and Seleucus Nicator, self-proclaimed King, by the time we begin. Greek traders had long-since been visiting west Indian trading ports, trading in fabrics, gemstones and spices, and indeed, many of the ancient names we have for these locations appear also in Greek, or show Greek influence.

Last of all, since we only have one start date, we have wanted to include as many interesting things as possible in it. This means that we have also tried to identify interesting states that can reasonably start as subjects of others, rather than directly owned by governors, both to better cover the political realities of far off regions like northern Anatolia or Judea, and to allow the player the choice of taking over the reins of many unique polities in these regions.

Over the course of development, we have used a great number of sources, texts and maps in order to craft what we believe, is an immersive, living world, which is as close to history as is possible. One invaluable reference tool for our Roman areas which deserves special mention, is the Digital Atlas of the Roman Empire, compiled at Lund University, using data from the Pelagios Project.

Additional sources include (but are far from limited to):

The Schwartzberg Historical Atlas of South Asia
An Atlas of Ancient Indian History - Habib & Habib
Perseus Digital Library
Pelagios Project
Pleiades Gazetteer

It should be noted that while these have been great resources we have sometimes had to take liberties to create as full a map as possible. As such, any errors are likely to be ours and the reference materials we have used should not be faulted. :)

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The Resource System - DD#3

First of all, we have gold which you gain from tax and trade, and spend on development and military. The second resource is manpower, which is required mostly for building and reinforcing armies.

There are also four other types of resources, which do not scale with growth, but instead act as a great balancing tool against snowballing always being better.

These four resources, are referred to as power. There are four types of power in Imperator, each corresponding to a character attribute . Each with their own use and benefits.

You primarily get power from the quality of your current ruler, but there is also a bonus in monthly power for having your national ideas match the categories your government want ideas in.


The first power is the Military Power, which represents the ‘Virtus’. This is based primarily of the martial abilities of your ruler. Military power is used to get new military traditions, inspiring devotio, as well as all unique unit abilities.


The second power is called Civic Power, which represents ‘Gravitas’, and is based primarily on the finesse attribute of your ruler. You use civic power to get inventions, set up trade routes, and moving your pops about, amongst other things.


The third power is the Oratory Power, which represents the ‘Dignitas’ This is based on the the charisma attribute of your ruler, and you spend this power on Fabricating Claims, Improving Relations, Enacting Laws, Endorsing Parties and many other things where a silver tongue is useful.


The fourth and final power is Religious Power, also known as the ‘Pietas’. This is based on the zeal attribute of your ruler. Some of the things you use religious power on is to stab pigs, convert pops and call omens.

Then there is lots more of abilities and interactions, that may or may not use a combination of power to use, but your technology progress is depending on your citizens output, not on your spending of power.3.thumb.png.24bf5c3a5664afbaa77c1a436de1d420.png3.thumb.jpg.d27caa1e589024d05e7df0bc825c6fed.jpg

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Units - DD#4

Light Infantry: These units can assault, and can be built by everyone. They are are cheap and quick to build, but weak against every other type of unit.

Heavy Infantry: These units can assault, and require the iron trade-goods to be built. They are not cheap, but are really good against cavalry, light infantry and chariots.

Archers: These units can assault, prefer to fight from the second row, and can be built by anyone. They are good versus infantry, but weaker versus cavalry. They are cheap and fast to build.

Horse Archers: These units prefer to fight from the second row, and require the steppe horse trade-goods to be built. They cost similarly to cavalry, and are deadly to slower moving units.

Light Cavalry: These units prefer to fight on flanks, and require the horse trade-goods to be built. They are not very expensive to build, and move very quickly. Weak against most units, but strong against archers and light infantry.

Cavalry: These units prefer to fight on flanks, and require the horse trade-goods to be built. They are more expensive to build, and move quickly. Countered by heavy infantry and War Elephants, but very good against everything else.

Camels: These units prefer to fight on flanks, and require the camel trade-goods to be built. They are quick to build, and move quickly. Strong versus lightly armoured types.

War Elephants: This unit requires the elephant trade-goods be built. They are very expensive to build, but are very good against units that can not quickly run away.

Chariots: These units can be built if you have the celtic or mauryan traditions. They are rather cheap to build. They are very good against light infantry, but weaker against other units.


One interesting thing for modders is that you can add and make as many unit-types as you’d like, as units are coded using simple text files.

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Population mechanics - DD#5

The population in the game is divided into population units, or “pop” for short, just like Vicky or Rome1.

Each individual pop has its own religion, culture and happiness . So yes, there are minorities in Imperator!

While there are ways to increase happiness of pops, including ideas, inventions and access to trade-goods, they tend to be less happy if they are not of the same culture-group, or if they belong to a different religion. Happiness impacts two thing on the pop, first of all, a pops happiness directly affects how productive they are. Secondly, low happiness increases unrest in a city.

There are four different types of pops in the game.

Citizens - They provide research and commerce income. These represent the patricians in Rome, and nobility in monarchies
Freemen - They provide manpower. The plebs of Rome is included in this group.
Tribesmen - These provide a tiny amount of manpower and tax income. These are the barbarians or uncivilized parts of your areas.
Slaves - These provide tax income

So how do you get a more pops in a city?

First of all, there is always a single pop either in growth or decline, depending on the population growth of the city. When this pop is fully grown or totally dead, either a current pop is picked for death, or a new random pop is created that will slowly grow.

Terrain, Civilization value, amount of pops in the city and access to trade-goods impact the growth in a city.



Another cool modding aspect is that everything that costs power, manpower or money use the same “price”-mechanic internally, so you can base everything on money if you so desire.

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The economy and buildings - DD#6

First of all, we have Tax income. As mentioned in the chapter about pops, the tax income of a city is primarily based on how many slaves you have in that city. Then of course there are several modifiers that affect it, like access to trade-goods, stability, ministers, and some factions when in power may increase your tax income.

Secondly there is Commerce. This is only present if you either import or export trade-goods from a province. Each tradelink provides some income, and then the amount of citizens you have increase it, while marketplaces and other factors can increase it as well.

There are also various economic policies that affects your income and expenses on a country level, but we’ll go through these in a later development diary.

Finally, each city has a few building levels. Each city can have at least 1 building, and each additional 10 pops in that city allows another building level.

Currently these are the effects of the building types, but that may change during development.

Training Camps : Gives +10% Manpower, and +10% experience to units built in the city.
Fortress: Each gives +1 fort level.
Marketplace: Each gives +20% Commerce Income
Granary: -1 Unrest and +10% Population Growth

Each building type can be built multiple times, and if you have 4 slots in your city, you can fill them all with Granaries if you so desire. Of course you can order the building of multiple buildings in a city at once, and they will be built in a queue.6.thumb.png.bcf1038af778cb32964d42b428826a61.png6.thumb.jpg.e0c205186755c6f7bd9ea001a6b4c268.jpg

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Characters - DD#7

The characters in Imperator are deeply detailed, and together with the pops and the politics are part of what makes a vibrant living world.

They have portraits that age gradually, with lots of different ethnicities covering the world.

There are four attributes that characters have.

Martial represents a character's ability to fight and lead troops. Characters with high martial skills make excellent generals.
Charisma is a character’s ability to charm and persuade others.
Zeal is a character's ability to inspire faith in other characters, and also in calling upon the favour of the gods.
Finesse represents a character's skill in disciplines requiring a high attention to detail. High finesse characters make excellent researchers and governors.

For those of you that played the original Rome or the Crusader Kings series will not be surprised to hear that our characters have traits. Traits on a character can be gained or lost.

Traits can be categorized in the following categories.

Personality - This includes being Brave or Coward, Cruel or Merciful. These impacts the character attributes and stats directly, as well as….. :)
Military - Usually a character has a maximum of one of those, that may give a bonus or penalty
Health - Stressed, Maimed, Lunatic etc. Not beneficial to the character in most cases.
Status - Some exceptional traits that can be given from actions, like Conqueror

Traits can also unlock a variety of unique event options, each tailored to the specific trait in question. Those of you familiar with CKII will be (dis)pleased to see the return of the Lunatic trait.

A Character also has his or her personal wealth, and four primary stats.

Popularity - Popularity is a measure of how the people see the character. In republics high popularity characters are more likely to elected leader of the republic. However even monarchies cannot ignore popular people.
Loyalty - Loyalty is a measure of a character's loyalty to the state. Disloyal characters are more likely to cause problems to a ruler than loyal ones. However even the most loyal of characters has their limit.
Prominence - Prominence represents the fame of the character. Jobs and titles help bring characters to public attention.
Corruption - Corruption is a measurement of this character’s willingness to engage in underhanded practices. Greed, bribery and the bending of rules come hand-in-hand with high corruption.

Characters have parents, will be able to marry and get children, just as you’d expect. They can also have friends and rivals.

Characters can be given various roles. Besides being ruler of a country, they could be assigned to govern a province, command an army, handle research or be given a role in the government. Some countries allow women to be given offices, and some do not.

There are lots of different interactions you can do with and on your characters, including arranging marriages, bribe them, loan from them, or even sacrifice them if your religions so permit and desire. There will be a deep development diary on those later in development.7.thumb.png.1faae6cb82ba0517c2fd8d09102c73cd.png7.thumb.jpg.36d24e5c167bff778f8ef544a65b5a1e.jpg

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So my thread wasn't good enough? :p

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It certainly is mate, I've made this thread to collect hard data only, so we can have a text and image store of everything we know. I saw your thread as a place to chat about the upcoming game and share links to other offsite resources.

Hope I didn't step on your sandals....... ;)

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No, you did not. But in my experience any thread on a topic becomes a chat for the topic. I try to post links to tweets and dev diaries already. :) Perhaps we should keep to one thread? We can use yours if you want. But bear in mind if you plan to have one post per dev diary in the start of the thread, we are getting one a week and the game is due out Q1 2019. So 7 might not be enough. :)

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Let's see how things play out. I reserved the first 7 posts so I could collect all the past DDs in a row. The OP will have an index, so we can jump to any particular topic as needs be going forward.

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I don't use twitter, so if you could continue monitoring that channel that would be awesome!

Also, I think I burned myself out with my pre release coverage of Civ6, so I'll be adopting a much lighter touch with I:R, probably keeping up with DDs and watching Youtube content only. I certainly won't be drilling down to the nth degree like I did previously.

Many hands make light work! ;)


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Sure. :) Today's teaser:



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Sweet! :b:

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Trade - DD#8

Trade in Imperator is about getting access to goods for your cities to make them better, and meanwhile earning money on the trade happening. A Trade-Route is defined as the import of one trade-good from another province, either foreign or domestic, where it is in surplus, to one of your provinces.
You can always import any trade goods you have a surplus of from your other provinces, but from foreign nations you need to have negotiated trade access first, and if you fight a war against each other, the import will be cancelled.
A province can only export if that province provides a surplus, ie, if it in total produces more than 1 of that trade-goods. A city produces 1 trade-good, and for each additional 30 population it produces an additional +1 trade good. There is no limit to how how many exports a province has, other than the amount of surplus goods it has.
You can always import a trade-good if you already have a surplus of it, and that gives you a smaller additional bonus.

Surplus in the capital province gives a special bonus on the country level and Surplus is clearly indicated in the UI.
Only the capital city in each province gets the benefit of the stacked goods. The other cities in that province get counted as they have access to 1 of the trade-good. Only the province stacking bonus can be applied multiple times, so you can import 20 grain if you so desire to keep up a huge population.

Please remember that creating a new import route costs you civic power!
As default you can import one trade good to your capital province.
There are multiple ways to get more allowed import trade routes to your provinces. Larger nations get more import trade routes to their capitals, there are ideas that allow more import, and there are inventions that can either increase all provinces trade routes or the capitals. There are also economic policies for trade, where you can forgo your income from trade for having more trade routes, or the opposite.

Income from Trade uses something we call Commerce in this game. Each Commerce level building in a city provides +20% Commerce to that city, and citizens will also provide a level of Commerce. Trade Income is based upon total amount of trade-routes in & out of a province multiplied by Commerce.



The List of trade goods include the following..
Grain, Salt, Iron, Horses, Wine, Wood, Amber, Stone, Fish, Spices, Elephants, Base Metals, Precious Metals, Steppe Horses, Livestock, Earthenware, Dyes, Furs, Olives, Leather, Woad, Marble, Honey, Incense, Hemp, Vegetables, Gemstones, Camels, Glass, Silk, Dates, Cloth, Papyrus, Wild Game



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Today's teaser, an impressively detailed trade map! The unfilled areas are probably(hopefully!) mostly unfinished areas, as even some of Italy is unfilled. ;)



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In The Map DD (#2) they mentioned that some areas will be unpassable (Sicily has 4 such areas). I wonder if some of those blank areas are unpassable?

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10 hours ago, Penry said:


In The Map DD (#2) they mentioned that some areas will be unpassable (Sicily has 4 such areas). I wonder if some of those blank areas are unpassable?

Johan replied to me yesterday:


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Looking forward to the next dev diary!


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Diplomacy - DD#9

Imperator follows the “new” generation of games, if we still consider CK2 new, in that opinions are two-way, where you can love someone that hate you, and you can see in detail what is causing the numbers to be that way. And, as has been common in our games since CK2, the AI will tell you exactly why it will accept or decline a certain diplomatic action.
Aggressive Expansion is a concept we liked in EU4, but it was awkwardly implemented. In Imperator we have an AE value in your country, kind of like badboy in older games, so you can see how it is decaying etc. This is then applied in the opinion calculations with each nation, depending on where they are and their status with you.

A nation, depending on its rank, can have a number of diplomatic relations. Each Alliance and Tributary counts as 1 relation, while a defensive league occupies just 1 slot, no matter how big it is. For each relation over your limit, all your power costs are increased by 10%.

One cool new thing in Imperator is the Defensive Leagues. This is a purely defensive alliance that allows multiple nations in it, and it is defensive towards anyone outside of the league attacking it. The leader of a league is the one that invites people in. A defensive league takes only 1 relation slot, no matter how many members. Only City States and Minor Powers can be members of a Defensive League.

The Diplomatic Actions include the following.

  • Declare War / Sue for Peace
  • Offer/Dissolve Alliance
  • Proclaim Guarantee
  • Ask/Cancel Military Access
  • Offer/Cancel Military Access
  • Demand/Break/Cancel Tribute
  • Request/Cancel Trade Access
  • Support Rebels
  • Fabricate Claims
  • Invite/Kick/Leave Defensive League
  • Improve Relation
  • Send Gift
  • Intervene in War
  • Threaten War
  • Enforce Peace
  • Sell City



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Today's teaser:


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These impassable areas are going to make things very interesting!

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Country Rank - DD#10
Each country in the game is determined to be of a certain rank, depending on their size, and different ranks give different bonuses and abilities. Please be aware that all values will be tweaked constantly during development.

City State
This is only possible if your country is only 1 city large. A City State can be a part of a defensive league, and have the following bonuses.

  • +20% Commerce Income
  • +20% Defensiveness
  • +1 Diplomatic Relation

Local Power
This is countries that have less than 10 cities. Local Powers can be part of defensive leagues, and they have the following bonuses.

  • +2 Diplomatic Relation

Major Power
This is countries that at least 10 cities. They can use the diplomatic abilities Threaten War and Guarantee, and they have the following bonuses.

  • +3 Diplomatic Relation
  • +1 Trade Route in Capital
  • +1 of each Power for matching Ideas to Government Form for a total of +2.

Great Power
These are countries with at least 20 provinces, and that are not subjects of other nations. They can use the diplomatic abilities Intervene in War, Enforce Peace, Threaten War and Guarantee, and they have the following bonuses.

  • +5 Diplomatic Relation
  • +2 Trade Route in Capital
  • +2 of each Power for matching Ideas to Government Form for a total of +3.


Intervene in War
You can join on any side in a war, where you have good relation with the warleader.

Enforce Peace
You can force a white-peace on a nation in a war, if you have good relations with their enemies.

You can protect any nation of lower rank from being attacked, giving you casus belli on anyone attacking them.

Threaten War
You can use a claim, to demand a nation to secede a city or province to you, to avoid an expensive war.

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