The Evolution of Warfare in Europa Universalis IV

By Joe Robinson 25 Oct 2016 0

Europa Universalis IV is in many ways Paradox Interactives’ flagship title right now– Crusader Kings II may have rocketed the company’s grand-strategy business into the mainstream limelight, but EUIV was really the first game to truly benefit from the influx of attention, funds and the new design philosophy debuted by the merry medieval murder simulator. Newcomers like Hearts of Iron IV and Stellaris may have benefited and iterated further and have the potential to be more popular, but it’s still early days for those guys.

We wouldn’t consider Europa Universalis to be a wargame, strictly speaking, but warfare is never-the-less at the heart of the experience – it is the main driving force of change and progression for the players and the game-world. Waging wars in EU has changed significantly since launch, so we thought we’d take some time to look at how it’s evolved and how a player’s approach to warfare has had to change over time.


To assist us we spoke to Johan Andersson, one of the most influential voices at Paradox Development Studios and front man for a lot of the changes we talk about below.

Laying a Foundation

300+ hours, three years and nine expansions later it’s hard to accurately remember what warfare was like during the early versions of EUIV. It was simpler, certainly – so much of what makes this game great was added or iterated on in later expansion. For Johan (and as far as warfare specifically was concerned), the launch version of EUIV really only had one job:

“We liked the basic combat then, with the units fighting on a battlefield, having regiments fighting – we thought that was fun. What we really didn’t like was the ‘ping pong’ that that was common in a lot of our games.”

“You would win a battle, then you would chase them to the retreating province, fighting there, chase them again… we really didn’t have any great solutions for that back then. For EUIV we did something called ‘Shattered Retreat’ – when your army lost it had to retreat quite far back, which gave the winner time to take provinces and siege fortresses. It helped make battles more decisive.”

Not having spent a lot of time with EUIII personally I’m not familiar with the “ping-pong” from those days, but EUIV’s initial war offerings were sturdy enough and it got the job done. Warfare in those days was relatively straight-forward and while the shattered retreat mechanic did certainly buy a player some extra time, it’s a matter for historians to debate whether it could actually be called ‘decisive’. It was generally good practice to chase that retreating army to finish it off quickly anyway, as it would always come back if left alone.

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General war-strategy was quite basic as well – with the enemy army defeated or at the least out of the way for a spell, you would then carpet-siege as many provinces as you could to prevent the AI rebuilding its armies. Any fortified provinces would take slightly longer to wear down, but with persistent and attention to what the enemy was doing, you usually didn’t have to worry too much.

The Art of War

Europa Universalis IV’s first three expansions focused on elements like trade, republics, governance and the all-important ‘New World’. It wasn’t until the fourth expansion that warfare got any kind of major improvements.

2014’s Art of War was mainly about features, improvements and quality-of-life changes and not about fundamentally changing the nature of warfare in the game – that wouldn’t come until the following year. The biggest change, as far as Johan was concerned, was making the terrain itself better suited for waging war. ESPECIALLY outside of Europe:

“We had a… challenge with EUIV from the start, mainly in the sense that it was Euro-centric. Everything favoured Europe, and the rest of world was generally something you conquered as a European power.”

“It didn’t really give a good military experience though having this disparity in province sizes, so the biggest change we made was evening out the province sizes across the whole map.”

Wars certainly became a more tactical affair post-Art of War. There were more provinces to move around in, facilitating very ‘hands-on’ army management as you orchestrated breakthroughs, flanking manoeuvres or retreats. The Euro-centrism of EUIV is still an on-going concern, but I certainly feel that at some level you have to bow to historical bias otherwise you’d be making an entirely different game… like Civilization VI.

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The rest of the changes can be summed up as above – quality of life improvements. Diplomacy and Warfare were tied closer together with some expanded Casus Belli options. It was made easier to recruit en masse and you could give objectives and behaviours to allied troops. Two new ‘special’ war events were also included to give Europe-based nations some set-pieces to deal with. In the mid-game, an abstraction of the Thirty Years War would trigger – called the Religious League War – where nations would fight over the religious policy of the Holy Roman Empire.

Towards the end of the game, Revolutionary France was supposed to trigger big-time and be a kind of ‘End Boss’, although Johan admits it didn’t really turn out as intended. It may be something they revisit in the future:

“The AI is never good enough to be a challenge in the end game, so no matter how strong we make them, it just was never there… Not to mention that few people actually got that far.”

This was all a step in the right direction, at any rate, but the best was yet to come.

Fort Paradox

The biggest and most profound change to warfare came in June 2015, about eight months later, coinciding with the launch of the Common Sense expansion. The DLC itself was actually focused on diplomacy and internal development, but the changes listed below came as part of the free patch that accompanied it.


Prior to Common Sense, Forts were simply another thing you could build in your provinces that helped somewhat with defence. There wasn't any tactical reason to place a fort in one place or another. The prevailing strategy mentioned above was still the norm, with Forts only prolonging the amount of time it took to siege a province down.

If you had the money, you might as well just build forts everywhere, making the conquest of an opponent's lands incredibly time-consuming- It became a matter of ‘When’, not ‘If’. It was something that Johan and his team were especially aware of:

“While warfare was fun in in EUIV, we felt it wasn’t as good as it could be. You’d siege down a fort, and then in the next province there’d be another fort, and the next… there was no tactical decision behind whether or not you should build forts, or where you should build them.”

“So we changed it so that Forts had zones of control to block movement and retake automatically adjacent provinces. We also made them more powerful, so you’d need larger armies to take them, and then also made them more expensive to upkeep.”

This was a complete paradigm shift in how wars were fought. The basic strategy of days gone by was still largely true, but the way a player went about it completely changed. You couldn’t just march up and down an enemy’s country at will – you had to take out the forts along the way, opening lines of movement and taking key strongholds. Carpet siege to prevent fresh levies/mercenaries emerging took longer, so there were more chances for enemies (or yourself, if you were on the losing side) to re-group and try again.

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It was a great step, but an imperfect one – through extensive play-testing it became apparent that placing forts in defensive orientated provinces – like mountains or hills – was actually counter-productive. They would make forts a little harder to take, but you couldn’t really defend yourself there as the game would treat YOU as the attacker if you tried to lift the siege on one of your forts, subjecting you to a bunch of horrific penalties.

That’s where the recently released Rights of Man comes in. It took over a year but the dev team finally made a subtle yet crucial change to how combat roles are assigned. Now, if an enemy army was besieging your fort, if you sent an army in to attack it you would be classed as the defender and the opponent as the attacker, meaning they’d suffer all of the negative penalties that come with having a fort there.

This meant that placing forts in natural border territories – mountains etc.… finally made sense, and smaller nations with favourable terrain could defend themselves more. A great strategy to employ now is to let an army knacker themselves out while trying to take a fort, and then pounce on them. Of course, if you lose the fort anyway it will be a pain to take back, but it represents an important shift in how to approach defending your nation.

Rule the Waves

Of course, it’s not all about the land combat. Naval warfare is also a key component of a EUIV game, although it varies depending on who you’re playing as. Colonial and Trade-based nations need to rely on navies more, but countries that are land-locked or are outside of Europe tended to have less of a focus. Johan’s thoughts on naval combat were quite clear:

“It’s a pain in the ass.”

Europa Universalis IV Mare Nostram expansion

“There’s no strategic-level game that’s ever had a good naval model, I don’t think. It’s such a hassle… we’ve done a lot of changes to it in EUIV and are generally happy with how things work, but it’s not as intuitive as land combat. It’s hard to make it into a game mechanic that goes beyond ‘Sit in Port because the other guy has more ships’.”

There is certainly an absence of the tactical depth land combat has managed to achieve with Naval warfare. Generally, as long as you have more ships than the other guy (and the right kind of ships) then you stand a good chance of doing ok, but if you can’t provide that all you can really do is sit in port and hope the province doesn’t get taken.

Navies get some interesting tools in terms of missions, but these are more an extension of your economy or your nation than of warfare itself.


Europa Universalis IV has had a bit of renaissance itself with the recent release of Rights of Man, which is welcome given how lack-lustre the last two expansions were. The team is showing no signs of stopping either; CK2 is still getting content after all, so we expect to see plenty more expansions in the year(s) to come.

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In terms of immediate changes Fort ZOC is being tweaked for patch 1.19 but Johan thinks that warfare is generally in a good place right now, so don’t expect any more major improvements or revisions any time soon. Having played a lot of Rights of Man recently with various nations and scenarios, I can agree that warfare is in a pretty good place right now – the key thing is really knowing how everything works and why.

Knowledge truly is power and Paradox still has some ways to go in terms of presenting information in an accessible form. We highly suggest players go to the wiki to look up key concepts such as forts and how the modifiers stack – once you’re armed with this knowledge everything will fall into place. Happy hunting!



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