This is the ninth in a series of reviews of Paradox’s empire management games. See the earlier reviews here:
Europa Universalis II: A Tale of Two Europas
Hearts of Iron: Europa of Iron
Victoria: Nineteenth Century Essay
Crusader Kings: A Dynastic Adventure
Hearts of Iron II: Return Engagement
Europa Universalis III: A Whole New World
Europa Universalis: Rome: Make a Desert and Call it a Game
Hearts of Iron III: One Plus Two Equals Three

While Paradox planned for two expansions to Europa Universalis III, they figured the game was finished after that. There were a number of small ‘sprite pack’ DLC and the like offered, but the game was done, and it was time to turn to other projects after releasing EUIII: Complete.

However, when they polled the fans on their forum for what to do next, more EU III content was the most popular request. And so, Europa Universalis III: Heir to the Throne was released as the third expansion at the end of 2009. This is a review of just the expansion, so you may want to look over my original EU III review (listed above) to better understand this one.

Putting ‘Grand’ in Strategy

I’ve talked about the map in previous reviews in this series (notably the EU III review). One problem the Clausewitz map had is that at a far remove it lost all details. It’s still useful, the political mode shows all the countries, and so on, but it’s just functional.

However, now we get something that has defined Paradox’s maps ever since: In the large zoom-outs, country names sprawl across the map, looking by turns magnificent and intimidating. This is made possible with code that adjusts the size and orientation of the words as the size and shape of the countries change. We’ve technically seen this before (during the HoI III review), but it was only introduced to that game with the later Semper Fi expansion. This is where the idea first shows up.

That said, the map is still less than impressive. The colors are muted, names (provinces or nations) are in a faded gray, and borders still have a number of odd glitches.

Whose Throne is it Anyway?

The new feature for which the expansion is named possibly has the least direct importance, but is an interesting tightening up of the model of pre/early-Modern politics. Any monarchical government has a succession, and the current heir is listed. The current and future rulers have legitimacy scores. The current legitimacy can give bonuses or penalties to stability, revolt risk, and religious tolerance. The successor’s legitimacy is based on the strength of his claim, and will normally be quite high. But ‘pretender’ rebels and civil wars are still possible, and if they win, will establish a new dynasty, which will start with a low legitimacy.

Since the age of the successor is now tracked, there can be a long regency that lasts until he gains majority (age 15). A regency council limits the diplomatic actions a country can take, and causes legitimacy to fall.

Finally, there is a chance for other countries that have a royal marriage to inherit the country. This might be a personal union, which is effectively a special form of vassalage, or a more direct inheritance. It is also possible to claim a throne in a disputed succession (which is whenever the legitimacy of the heir is too low), and the game has an alert listing all the countries currently subject to the problem.

Merchants, and Spam

The trade system got expanded with trade leagues and trade rights. Both of these are diplomatic options only available to merchant republic governments, and allow them to extend the reach of their Centers of Trade.

Trade leagues are like a special kind of alliance where all the members agree to send their trade to the leader’s trade center. In return, everyone in the league gets to use the best possible modifiers for trade and merchant activity available in the league. Trade rights get countries outside of the league to send certain goods to the trade center. This greatly expands the reach of certain trade centers, and boosts the money flowing through them, to the profit of the host merchant republic.

For some reason, these actions are set to pop-up message windows instead of just being noted in the log by default. With four leagues in action at the beginning of the game, this creates a lot of extra messages that are not meaningful for most players, especially since there seems to be a lot of churn in league membership amongst AI powers.

Not Holy, Not Roman, But Perhaps an Empire

One of the oddities of history that the EU series has always tackled is the Holy Roman Empire. It is depicted as a collection of separate states with a nominal head (the current emperor), that is, at best, first among equals. With its position in central Europe, what’s going on within the HRE is always important, but the Empire itself only has a light touch on the course of the game.

This was expanded upon somewhat from EU II to III, but it was still a fair amount of motion without a whole lot of effect. Generally speaking, there are a set of countries defined as electors, who choose the new Emperor every time the current one dies, and the Emperor always has the ability to march troops through the various territories of the Empire (normally this takes diplomacy to arrange), and has some freedom to intervene in wars among its members. (This is not a bad model of history.)

Now, there are a series of reforms that can be initiated. Assuming the Emperor can garner enough authority, the government of the HRE can gradually be strengthened. This is effectively a list of decisions available to the Emperor, that must be triggered one after another, that affect all the countries in the HRE. The member states also have to accept these reforms, which is part of what imperial authority does, and takes time and effort to build up to. The final reform, Renovatio Imperii, turns the entire HRE into a single big super-state controlled by the Emperor.

Ministry of Culture

The idea of army and naval tradition as a score that was used to create military leaders was introduced to the EU series from Victoria in III. Now, HttT has introduced cultural tradition, which allows you to create advisors.

In the original EU III there was a system of randomly generated advisors which you could hire to generate bonuses in particular fields. The advisors are still the same, and there is still a pool of available random ones, but now cultural tradition allows you to create one of the type you want/need—and there are 36 different types. They also come in different degrees of capability, and a high cultural tradition allows you to create more capable advisors.

In general, cultural tradition goes up during peacetime, and down during wartime. However, there are now also ministers, who can be used to boost cultural tradition; but this is merely the cheapest of their abilities. Ministers are like the colonists, merchants and diplomats that have been in the EU series from the beginning. Depending on the exact form of government you have, you get a certain number per year, which can then be ‘spent’ on various tasks.

EU III introduced provincial decisions along with the concept of decisions in general, and they have now been modified and expanded in HttT. Most provincial decisions were local trade-offs between two statistics, and for me, usually an unattractive tradeoff. Now there’s a more extensive list of them, including some that are minor upgrades to the province, kind of like the buildings that EU has always had. However, the ‘upgrades’ can only be done near the national focus, an area that you have decreed will receive bureaucratic attention, and that can only be moved every few decades. All the provincial decisions require different numbers of ministers to enact (up to 5 for some, which is the maximum number you can have at one time), forcing you to ‘budget’ your activities.

Why Are We at War Again?

The most important addition to the game is the Casus Belli system. The EU series has always had a robust diplomatic system to handle peace talks, but once at war, it didn’t matter if you started it, or were attacked, if you had a claim on some of that nation’s territory, or a different religion, the peace process was the same.

Now, it matters.

The new system defines different reasons (causes) for war, such as ‘alliance’ (your ally is at war with them), ‘trade war’ (someone has embargoed your merchant republic), ‘reconquest’ (someone else controls what your country considers to be home territory), or any of a couple dozen other reasons, some of which are granted by random events. These are meant to define the goals of a war, and will affect the prestige and infamy gained from the peace.

This ends up changing how the game generally works. It used to be that the punishment for declaring a war was a loss of stability, but with all these goals it is now easily avoidable. Instead, a new statistic is listed at the top of the main screen, infamy, and the game is much more about managing that number instead of stability.

Badboy was a concept added way back during patching of the original game in the series, and has slowly become more visible over time, and was renamed infamy either in EU II or III (not quite sure anymore…). The main idea was that taking territory increased this rating, and it would then slowly subside over time. If it went over a certain limit, the AI players would all start attacking that country in an attempt to keep it from running away with the game. The idea has gotten more nuanced through various iterations, and now the AI is responds better to shifts in infamy, up and down, including in other AI players. Any country that goes over its limit (which varies depending on the ruler and policy settings) now becomes eligible for the “Dishonorable Scum” casus belli from everyone else.

The amount of infamy gained from taking territory has increased from previous versions, but some war goals lower the amount again. However, defensive wars don’t (usually) have a goal, so taking territory when attacked is expensive, and the declared goal only applies to the country you declared war on, so taking territory from allies instead of the main target is also expensive.


Paradox had good reason to consider EU III complete after releasing In Nomine, but Heir to the Throne is a solid improvement. Most of the features came from suggestions from users on the forums, and Paradox managed to choose some very good ones, and implement them well. In addition, the interface does make a few things clearer than before. Most notably, Military technology has always slightly improved a number of combat modifiers, and these are now made visible in the military tab of the UI.

It is an expansion made up of feature creep, so I wonder if a new person would want to start without it, but then, the complications in HttT are largely lost in the vast sea of complexity that the EU series has always had. Certainly any fan of EU III Complete will find HttT an improvement.

However, I do need to mention one last flaw in the ointment: For some reason, the EU III: Heir to the Throne crashes upon exit on my Windows 7 machine. This isn’t really a problem, as there are no problems while playing or saving the game, and this occurs as the game is finishing its exit, but it does always give an error.