Europa Barbarorum features a new buildings system, with Government Buildings, new recruitment buildings, as well as other new types of building.

A more in-depth description of the EB Buildings system is further down.

The Governments system has been made to represent different ways of governing the provinces you conquer, based on historical sources. Each type of government gives benefits and drawbacks for unit recruitment, building availability, population happiness and squalor and so on.
As an example, while one type of government makes the population happier, it can limit your troop training choices in that province. Another type of government can give you access to the elite units of your faction, but in return it can hamper production of some buildings and have a profound impact on population loyalty. Below are some examples of Government Buildings.

New buildings have also been added, and some of the old building trees in RTW have been expanded (like level 4 & 5 buildings for the barbarian factions).

Since the map has become bigger, the 'Distance to Capital' penalty will increase, the bigger your empire becomes. Some buildings have been added to help counter that problem.

Many new religious buildings have been added, and as each faction gets at least four different temple chains to choose from, each devoted to a different deity, there will be a lot of variety for the player when it comes to religious buildings and the benefits they provide.

New unique buildings and wonders have also been added to the different cities, which give many different benefits.

An in-depth description of the buildings system:

Some of the buildings are basically ones that were present in RTW from the start, but every building has a unique new EB description to explain how they were used historically and alongside other structures you will find in EB (if the new description is not ready there is a placeholder, but no vanilla descriptions remain). The biggest changes you will notice will probably be in the new military buildings and in the government buildings.

The military buildings are referred to in shorthand on the forums as MIC’s (short for Military-Industrial Complex). The MIC represents the buildup of infrastructure in a province to support the raising, training, equipping, and logistical organization of the faction's military. One structure replaces not only the vanilla barracks, but also the stables and ranges, and portrays the other associated buildings that were necessary for the training of troops. These are unique for each faction, but they all begin as rather modest structures often like muster fields and they evolve over time into comprehensive facilities for the training, equipping, and housing of large armies. These structures are not tied to city levels any longer and a large one might be found in a smaller sized town, but do not make the mistake of thinking they are common. These buildings are extremely expensive and time consuming to build.

The types of troops you may recruit in each individual faction’s 'MIC' will vary greatly depending upon what type of government you have chosen to put into place in that particular province, so we now move into a description of those buildings.

Government buildings are different from core buildings. The core buildings do often represent the residence of the chief magistrate or king, and change as the city size increases (this is hardcoded), but core buildings will not be able to be constructed unless a government type is chosen for each new province you conquer. The types of governments available to you will vary depending upon the faction you will control. There are generally four types: a 'homeland' type, a 'colonizing' type, a 'subject state' type, and an 'allied state' type. Again, they vary greatly depending upon the factions, and there are some exceptions to this general pattern, but these are rough guidelines to help you understand the system.

Let’s take the Makedonian government types as an example for which we can provide more details: when you begin the game, the provinces Makedonia controls will already have governments put into place for you. These types of governments are based upon the types found there in 272 B.C. Makedonia itself would have a 'homeland' type (called a Patris Makedonike or 'Makedonian Homeland'). Thessalia would have a 'colonizing' type (called a Satrapeia Makedonike or 'Makedonian Satrapy'). The Peleponnesos would have a 'subject state' type (called a Nomos Symmachos Emphrouros or 'Garrisoned Allied State'), as would Euboia. And finally the island of Lesbos would have an 'allied state' type (called a Nomos Symmachos Autonomos or 'Allied Autonomous Territory').

These different government types give different bonuses and allow for the recruitment of different types of troops. They also allow or restrict different types of buildings for the province, but remember that they are necessary to recruit soldiers and advance city levels, so you cannot get along in the game without them. Back to our Makedonian example though... In a province with a Makedonian Homeland government, you can recruit the absolute best troops the Makedones can field. You can also construct the highest levels of buildings that exist in the Makedonian construction tree. You will probably have slower growth and maybe some trade penalties (laissez faire economics this is not), but the province would be more loyal and lawful and with your best troops trained there you would benefit greatly. These homeland governments can only be constructed in places where their actual homelands were, so you could not build one in Egypt, for example, for the Makedones. The drawback is that they are very expensive to build, and take a long time to construct, since the most loyal and most thorough expansion of your faction into a new province will take the most effort and time to ensure it succeeds. With this type of expansion, it is also logical that very few units made up mostly of 'foreigners' would be available for you to recruit in these areas, but it is possible that a few very simple troop types could be gathered together from the small numbers of natives you have allowed to remain in the province.

If you have conquered a more distant province, you could create the "second best" type, your “colonizing” type government. This is very much like the homeland type, but some of the absolute highest level buildings and troops cannot be built here. It takes a while to build and is still expensive, but it is not so much or so slow to construct as the homeland type. It is still your best choice once you move beyond your homelands, or even in some of your homeland areas if you have plenty of homeland types already. You will find a few local units (not normally of your faction’s style) available to you in these provinces, especially in the lower levels of the MIC’s.

The 'subject state' type will still allow you to create some of your good faction troops but you are allowing many of the natives of the province to continue their way of life alongside the new inhabitants of your faction. Your highest level troops are not able to be trained here, and your best faction buildings are not able to be constructed here, but there are plenty of other benefits to be gained. This type of government is moderately cheap and fast to create. Whether you are installing a 'puppet' tyrant to govern locally for you or whether you are allowing a local tribe to govern alongside some of your strongmen, the locals are able to create some moderately good military units themselves in these places (provided that such units can be created here by the locals). Trade is not so much interrupted by the uprooting of massive numbers of inhabitants, and you might find some other bonuses such as an increase in the happiness of the local inhabitants. But it all depends upon the faction’s particulars (as the Makedonians have a stronger garrison in this type, they have better law bonuses, but worse happiness penalties). Since your highest level structures are not able to be built here, it is advisable that before you place this type of government you note whether or not this is an already advanced province. If it is a very simple one, you might not be able to gain quite as much in the end as you would like.

The 'allied state' type is not recommended for smaller provinces for the same reasons. This is an ideal type to institute when you have conquered a large city with numerous good structures and a large population. You can still build many structures, but your best 'cultural exports' are not available. This province is now under your control, but there is minimal change instituted immediately. Trade continues unabated (and trade bonuses are granted), there is no large transfer of population (and bonuses to population growth are possible), and the people are happy (even if they are not as lawful or loyal to you). The government needs little money and can quickly be put into place in this type also. Only your simplest troops can be trained here, but if the region has any good or elite troops that your faction could recruit, they would definitely be available in this type of province (they would not be available in this province if you had instituted a 'homeland' or 'colonizing' type). The local troops trained here might also gain experience bonuses as you are not disbanding their familiar training centers and techniques.

An allied or subject state type government may be destroyed and a colonizing type instituted at a later date if you wish, but the same expenses (in constructing buildings more suitable to your faction’s peoples) and delays (in introducing colonists and changes in laws and such) you would have incurred earlier would still be expected if you initiated the changes later.

For much more information, read the descriptions of the possible government types for your faction. Be aware that the AI is not restricted by time or expenses in building their government structures. The best type available for each faction in each province will be automatically placed for the AI factions upon conquering the province. When you conquer a province, you may destroy the old AI factions’ government structures, and when you look at the types of governments available to you in that province you will see if all types are available or if that region is one where certain types are not possible.

Another new set of structures you will immediately encounter are the two types of ports. You are able to create moles and docks for merchant trade fleets in almost any province that has access to the seas. But these structures are not capable of creating naval fleets. A separate set of naval ports are needed for fleets, and these are not able to be constructed in every province. They will make competition for certain coastal provinces more intense, while still allowing sea trade to continue. Some of the best naval harbors are restricted even further as you will find, to the best harbor sites in the ancient world.

You will find many other building types new to you in EB also. From Celtic Hero tombs and River Ports (only available in certain provinces) to Pahlava Karwansarai and Pairidaeza, to Baktrian Buddhist Stupas, to Hellenic Heroa, Pontic Royal Monuments, Ptolemaic Stelai, Makedonian Advance Garrisons, Sweboz Thengaz, Yuezhi hunting grounds, Hellenic Hermai and new theater structures, colonies, granaries and grain silos, doctors, gymnasia, soaparies, Celtic baths and schools, game fields, and many more, you will find many new ways the factions have been more "personalized".

Religious buildings in Europa Barbarorum work in a similar manner as they did in Vanilla. Building a religious building in a settlement will give the settlement various bonuses, which increase as the religious building is upgraded, and can give the Family Members in that settlement Ancillaries if they stay in the settlement for a long enough period of time. The factions in Europa Barbarorum have a far greater number of deities to choose from than those in R:TW Vanilla did, and cities are no longer restricted to worshipping a single deity.
Religious buildings in EB represent the most important god or goddess of the city they are built in: represent a city's dedication to a certain deity: rather than representing a single religious building in a city. It is assumed that the city will also have minor shrines and temples built and other deities worshipped; in fact, in some cities, minor religious buildings can be constructed on the campaign map. These let a city honour a second official deity and receive some of the benefits that a primary religious building for that deity would bring.
Most cities will have a religious building already built at the start of the game, altough some will not. Some cities which were associated with a particular deity historically will have a religious building dedicated to that deity in EB, such as Athenai, which has a Temple of Athena at the start of the game. The patron deities of some cities, however, were much more difficult to determine and the EB team has placed historically accurate religious buildings in those cities to the best of its abilities. A city's primary deity is also restricted to the deities that are worshipped by its ruling faction. Something many R:TW fans had a problem with in R:TW Vanilla were the unrealistic bonuses given by religious buildings. The bonuses a religious building gives represent the impact the building itself and anything related to it (such as its priests), has on the settlement it is built in, as well as on the region and its inhabitants.

What about these 'unique buildings'?

There are many new structures we refer to as 'unique buildings' that are present in provinces at the game’s start. These are not buildable by the player or AI, but they do provide bonuses to most factions (some have better bonuses for particular factions or worse ones to others). Most of these are able to be destroyed by the human player, but some are not. These include many buildings (such as the temple of Apollo at Delphi, or the Mausoleion at Halikarnassos), complexes (such as that at the holy hill of Teamhaidh, or the Megalithic Maltese Temples), holy sites (such as the Nêrthuhárugáz, or the sanctuaries of the Ustyurt Plateau), tombs (such as the tombs of Cyrus, Alexander, the Pontic dynasts), or other unique structures (such as the Diolkos of Korinthos, or the Great Pyramids). There are some unique buildings that are indestructible though. These include some trade chokepoints (such as the Pillars of Herakles or the Bab El Mandeb), some other natural features (such as Lake Avernus, or the Sahara), some holy mountains (such as the ones at Sinai or Sleza), or even some traditional trade routes (such as the Silk Road, the Amber Route, or the Persian Royal Road). All of these will (we hope) add to the educational uses of the game as well as making it more personalized for each faction and more enjoyable to the player. The names of the unique buildings are determined by the faction or culture that controls it at the start of the game.

Also, you will quickly notice that a majority of the "constructed images" for buildings are not yet in the game. We focused on trying to get as many of the icons for buildings ready for the open beta as we could. There are currently so many constructed images (the larger rectangular ones above the buildings' descriptions) that it would be futile to compile a list currently of the ones that need adding. This situation will be rectified in subsequent builds, but for now the icons should be enough to make the open beta experience enjoyable.