Prepare For War Eu4

Prepare For War Eu4 5,5/10 8363 votes

First off, let’s not fall to finger-pointing of the laying of blame. It’s nobody’s business but your own why this article is suddenly relevant and important to your well-being. Europa Universalis IV [official site] is a game of ruthless caprice, where even slight mistakes, misjudgments, and lapses in attention can bring you to ruin.

  • Dec 17, 2015  Caution, Do not use feature 'Prepare for War' In the Ally Diplo feedback screen unless you have.20 FAVOR. submitted 3 years ago by Eric988 Just used Prepare for war, went to officially declare my war only to see a nice -1000 on both my allies for not having enough favor left.
  • If a war happens in this time, you might be screwed. You will want to have strong allies nearby, so you they can defend you in a war. Conversely, if they go to war, you'll only be able to send few units, so let's hope they can deal with it themselves. Before Westernization: This requires even more farsight.

Perhaps you declared war on someone the day before they hit a new level of military technology. Maybe you gambled that your enemy’s powerful ally wouldn’t actually bother to travel across Europe to fight you, but they did, and now they have arrived, unwanted and obligatory guests at your war, and they look hungry. Or maybe you just got unlucky, and your enemy had a military genius in their back pocket while you’re stuck with the equivalent of Ambrose Burnside.

Europa Universalis is a historical strategy game that simulates all aspects of world history from 1492 to 1792. Each player takes on the role of one of the major nations of the era, controlling diplomacy, economy, warfare, exploration, and colonization.

The point is, you’re losing a major war in EUIV, and you’re losing it badly. And getting out isn’t going to be easy. If it were easy, if it were just a matter of agreeing to a minor settlement, you wouldn’t hesitate. But no, this is a war that poses an existential threat.

It seems like all is lost. But this is why EUIV is a game where it pays to never give up, and never reload. The chances are, you can not only survive this crisis, but come out of it almost unscathed.

You might be watching a rout unfold, but here is how you turn that into a victory.

First Principle: Stay Alive

If you can’t win pitched battles, you need to give up on the idea of fighting them. The most important thing you can do when a war is going wrong is to keep a credible army in existence.

It doesn’t have to fight. God no. That’s defeats the whole purpose. It’s more like the naval strategy of keeping a “fleet in being“. As long as you have an army in play, it’s something that forces the enemy to stay relatively concentrated in case you decide to fight. If your enemies spread out across the countryside to start dismantling your nation, your ineffectual little army can attack the small siege detachments and start whittling down their strength. If they group up to fight, you melt away.

Remember, siege progress resets once the besieging army moves, so just forcing them to respond to your army is a victory that causes the war to drag-on.

Playing a “where’s my army” shell-game is easy to do if you have a fairly extensive country. Russians can always withdraw deeper into Russia, for example. But what if you don’t have enough space to protect your army?

Easy: you create some.

Second Principle: Gaining Space


You can’t hold ground in battle, so you need places to run and hide. Your own territory is being overrun, so it’s time to look to your neighbors.

Find neighbors who don’t hate you, and ask for military access to their countries. If all your neighbors hate you (all of them?!) then we may need to talk about basic diplomacy. But chances are, you have some people next-door who are happy to lend you a cup of sugar, jump-start your car, or let you conduct guerilla warfare from their sovereign territory. In that case, you open the diplomatic relations window, go to “Access Action” and “Request military access”.

The trade-off here can be significant. Agreements with other countries count as “diplomatic relationships” against your country’s maximum. You can go over those limits, but each extra relationship costs you a monthly diplomatic monarch point. If the war drags on for a long time (and a long war is your best chance here), those lost points will add up, and cause you to fall behind on the naval and economic technologies that those points would have bought.

But getting military access is worth it when things are dire. The enemy can chase you and fight you on neutral ground, but they can never occupy the territory, and therefore they’ll have to contend with the fog of war. Neutral territory becomes a perfect place to hide.

Or from which to launch sneak attacks. Another way to pull enemy troops off your territory is to open a circuitous passage through neutral countries from your territory to theirs. If they’re running short on troops, you can usually force a significant recall of forces from your homeland simply by laying siege to their capital for a couple weeks. Even if you get caught out, your army will probably be able to retreat to safety and partially rebuild itself before the enemy’s pursuit catches up.

Of course, to rebuild an army requires soldiers, and here’s where we encounter some controversy.

Third Principle: Lives Are Cheap, so Buy Them

Mercenaries are as much a source of debate in EUIV as they were for statesmen in Machiavelli’s day. There are players who refuse to use them except in the most dire circumstances. If you wage an extended war via mercenaries, you will end up paying off the debt for decades. They are economy-crippling, game-stifling money-sinks.

But it’s all gone wrong? I love them.

There are a lot of negatives associated with mercenary troops: their upkeep is far higher than a standard national army. They cost a fortune when they’re replacing losses.

But those are problems for later. In the desperate short-term, mercenaries work. They will fight for you when there are no more able-bodied soldiers to recruit in the kingdom. Mercenary regiments will form within days of hiring, making them perfect for those times when your country is being overrun by enemy armies. They are an almost-bottomless resource if you don’t burn through them too quickly, and their deaths only cost you money. And even if you don’t have money, you can always borrow some.

Mercenaries enable you to keep bleeding your adversaries, harassing them, and denying them an ultimate victory.

The alternative is capitulation. I don’t recommend it.

Fourth Principle: No Surrender

If wars like this were easy to escape, we wouldn’t even be discussing them. What’s scary is when your enemy is coming after you and won’t accept even absurdly generous peace terms. At that point, you have no idea what you’ll be left with once the fighting stops.

For anyone less than a great power, a punishing peace settlement can be devastating. Your best provinces might be taken, your country split apart, and a hated, once-conquered enemy brought back to life. There are a lot of ways a peace settlement can undo hours and hours of work and deal your game a setback from which it is very hard to recover.

But you can only influence the outcome as long as you’re still able to resist. If you just “think of England” and try to get your defeat over with, you are basically risking your game on a peace settlement you will not be able to affect.

Fifth Principle: Know Your Enemies… and Their Enemies

Even when you’re only at war with one country (which is rare, given how often EUIV is a game of alliances), you need to identify the diplomatic weaknesses in your opponent or opponents. Check out who is fighting against you by clicking on the “war score” button the appears at the bottom of the screen when you’re at war, then take a look at who is lined-up against you.

The nightmare scenario is that you’ve got a formal Coalition arrayed against you, because at that point a separate peace becomes impossible. Coalitions are deadly in EUIV because they are collective wars, where every member is committed until the bitter end. You just have to try and hold out until the war-leader calls it quits.

But coalitions are also rare. Most of the time, what you’ll be facing is a standard set of alliances. And at that point, you need to figure out who in that alliance really hates you, who is just showing up out of obligation, and who can be made to have other problems.

Usually there are only one or two real opponents in any war. Those smaller satellite powers who send small detachments? They are good targets for your army. Give them a bloody nose and they’ll probably leave you alone for a while, then come asking for a White Peace later.

The remaining enemies have to be defeated or simply exhausted. The good news is that they can become the focus of your diplomatic efforts. Or, more accurately, their neighbors can.

It’s very rare that you’ll be able to bring help into a war. Most AI nations are smart enough to see there’s little point in joining someone else’s war, especially when it’s already in the process of being lost. Still, it’s worth it to try. Even if you can’t get a friend in the middle of the war, a postwar alliance can help you stay safe after the fighting stops.

But it’s also good to just familiarize yourself with your enemies’ enemies. If they have serious rivals (and the diplomacy window helpfully shows who each nation’s main rivals are), then the odds are good they’ll find themselves fighting another war on another front if you just hang on long enough. I’ve started more than a few national collapses by sucking enemy powers into an endless quagmire, then watching in glee as they get ganked by their rivals and torn to pieces. That’s why you should know your enemies’ diplomatic relationships as well as your own.

Sixth Principle: Picking the Time and the Place

It’s important to set expectations for the rest of the war. You’re probably going to lose a lot of battles. That’s the whole reason you’re in this mess: you can’t win the fights.

So what you’re trying to do is notch small, slight victories that will improve your war-score and inflict casualties on your enemy. Most siege detachments only number a few thousand men, so even a small army can usually overpower them before reinforcements arrive on the battlefield.

Usually, but not always. There will always be battles that drag on just a day too long, giving the main enemy army time to arrive and crush you. But that’s a risk worth taking. Those types of battles tend to be bloody for both sides. You lose, but you had days of combat with smaller detachments to inflict casualties. Very occasionally, you’ll get lucky and the enemy will feed troops into battle piecemeal, letting you defeat far superior forces. A single bloody debacle can change the entire complexion of a war, and put your foes on the back-foot.

If you can manage it, it’s also worth trying to find a highly defensible province. Don’t corner yourself (no matter how good the terrain, this is not a road you want to go down), but keep an eye open for provinces with mountains, rivers, or even dense forest. These are good places to bait a fight. If you can get their first, you will enjoy a huge defender’s advantage.

They don’t have to be your own provinces. Again, invading enemy territory can sometimes let you provoke a battle on good ground. Austria, for instance, is easy to lure into an Alpine death-trap. Will you win? Maaaaybe. Will you at least kill a lot of enemy soldiers? Absolutely.

Final Principle: Know When to Quit

Now here’s an odd phenomenon I’ve noticed near the end of particularly hard-fought wars in Paradox games: they get personal. Decision-making gets more and more detached from pure reason. I don’t just want to win the war, I want to humiliate the make-believe person I’m playing against.

It makes sense. Fighting a war like this takes intense determination. Otherwise you’d give up, or start a new game, or go play something else. But to stick it out, for session after session of grinding attrition? That’s something you do out of spite and anger.

But when it comes time to call it a day and make peace, those same feelings can start whispering bad advice: “Hey, screw those guys. You don’t need to take this offer. After all the crap you’ve been through, they should be offering concessions to you.”

But that’s just Pride talking.

There are times when it’s worth it to keep fighting. If your opponents are suddenly collapsing, and are beset by other enemies, it could be worth it to push your luck to try and nab some territory or financial reparations. Continuing the war also postpones the post-war, which is going to bring a lot of complications on your head.

Still, when your opponents are getting dragged into other wars and starting to teeter, and the game is swinging in your favor, you need to remember that peace is a game of musical chairs. If you press your luck, and your enemy manages to reach settlements with their other rivals, you might be right back where you started, except now you’re already exhausted down to scraps. If it goes wrong again, your position is likely to be irrecoverable.

In general, if you’re offered mild peace terms or a White Peace? Take it, and chalk it up as a victory.

Winning the Peace

As bad as the war might have been, the aftermath can be worse. Broke, crushed by debt, low on manpower reserves, and almost certainly with slightly less territory than you started with, it can sometimes feel like you fought an epic war just to achieve a Pyrrhic stalemate.

Prepare For War Eu4

But don’t get discouraged. You have a truce that will protect you for ten years, which should let you partially de-mobilize. Once you’re not spending oceans of cash on warfare, you’ll be stunned how quickly you can start paying down your national debt.

The first step is to consolidate under-strength regiments. Replenishing regiments is expensive, so if you have a bunch of units down to 10% strength, they are costing you much, much more than would one unit at full-strength. That said, don’t rush to consolidate artillery or cavalry regiments. Those are expensive to establish, so it can be worth it to leave them around so they can come up to full strength without costing you the start-up costs of a new unit.

The second step, once you know how many full regiments you have, is to dismiss as many mercenaries as you safely can. Get those mercenaries off the ledgers, and that should give you a positive cash-flow.

Your biggest threat during peacetime (excluding predatory neighbors) is the unrest related to War Exhaustion, and the most extreme form of this is The Peasant’s War. This is a capital-D Disaster (if you want more detail on how they work), one of only a handful in EUIV. Peasant’s War is a long fuse leading to national collapse.

When your national manpower is low, the peasantry will start getting angry and a percentage will start counting up to 100. At 100, Peasant’s War triggers and your national unrest goes through the roof. Progress goes faster if you have more than 10 loans (which of course, by now, you do) and high war exhaustion. Peasant’s War is not a game-ender, but it does mean that you probably won’t have a quiet, uneventful peace for licking your wounds and retrenching your empire.

See the problems here? On the one hand, you’ll need to retain at least some of your mercenary army to quell potential revolts and discourage your neighbors from descending on you like a pack of hyenas. On the other hand, your ruined finances desperately require you to reduce your army to a shell of itself so you can pay off debt and address some of the root-causes of looming disasters.

A good compromise is opening your finances tab and reducing the funding for your armed forces. It will lower their morale and make them more brittle in battle, so I don’t recommend pushing the slider lower than 33%, but it’s an easy way to fix your cash-flow without dismissing all your soldiers.

Surviving peacetime after a near-miss of a war is like taking a ship through a minefield, and there’s no surefire recipe for doing it successfully. But in general, you keep just enough troops around to put down revolts, and then pay off your loans as quickly as possible. You will lose years’ worth of progress as you fire advisors and forgo building infrastructure. But it will help you get out from under the crushing cost of war faster.

What it’s worth

So why did you go through all of this? Chances are, if you survive this war, you spent the better part of five or ten years fighting, and then another ten or twenty years dealing with the fallout. All to stay in the same place.

Except that’s not really true. Europa Universalis is a game in which windows of opportunity eventually close. The person who is kicking you all around the map in 1480 is taking one of the best shots they can. They have the right alliances, the right diplomatic situation, the right technologies, and the right army and commanders. If you can survive in the face of all that, they may never again be able to pose such a threat. Especially because they will have squandered all those resources trying to break you. Yet there you stand.

Warfare is one of the primary ways to obtain territory and other concessions from other nations. The technical aspects of maintaining a military machine and its employment on the field is discussed in-depth in the articles land warfare and naval warfare.

  • 1Starting a war
  • 2Sides in a war
  • 4War Exhaustion
  • 5Warscore
    • 5.1Occupation
  • 6Sue for peace
  • 7Negotiating peace
    • 7.1Warscore

Starting a war[edit]

Like most diplomatic actions, declaring war requires a diplomat. War may not be declared on an ally, a subject, a guaranteed nation or a nation transferring you commercial power without first breaking that relation.

Casus belli[edit]

Main article: Casus belli

The aggressor may pick a casus belli when declaring war. This determines the wargoal, the options available in the subsequent peace deal, and their associated costs in warscore, aggressive expansion, and diplomatic power.

Declaring War with a Casus belli

No casus belli[edit]

Declaring war without a casus belli will result in -20aggressive expansion, a -2 drop in stability, and +2war exhaustion. These penalties are halved with full Diplomatic ideas.

Good relations[edit]

A country declaring war on another whose opinion of them is higher than 100 will cause -1 stability and +1 war exhaustion.If opinion is higher than 150, penalty increases to -2 stability and +2 war exhaustion.


If a country is not marked as a co-belligerent:

  • That country can't call its allies to arms in that war (but its subjects are called as normal). Beware that the Holy Roman Emperor defending the empire is always a co-belligerent.
  • Taking that country's provinces in a peace incurs +50% aggressive expansion and costs +100% warscore.

If a country is marked as a co-belligerent:

  • That country can call on its own allies to fight as well
  • If that country has a guarantor, it is called also
  • Taking that country's provinces will cost the same as the war leader's provinces

Sides in a war[edit]

A war consists of two opposing sides of one or more countries. A side may be made up of a coalition, the emperor, allies or the defender of the Faith who honour their treaties and/or vassals and other subject countries.

War leader[edit]

The war leaders are denoted with a star in the war screen. The war leader on the attacking side is the country that declared the war, while on the defending side the leader is the country on which the war was declared (the target of the war goal). For each side in a war the leader is the country that may call in its allies and may negotiate peace on behalf of all their war allies, simultaneously ending the war for everybody. They may negotiate a separate peace with each of the hostile belligerents, except subject nations or coalition members. They may surrender territory of their war allies, but not their treasury.

When a war leader is annexed in a separate war, one of their allies will become the new war leader. The new war leader can call their own allies into the war if the war has not lasted long enough to close the window for calling allies to it. If the war leader is vassalized (by event or force) the new overlord will become the new war leader and can call their allies with the same caveat about calling allies to long wars.

Military and port access[edit]

All nations on the same side in a war will have immediate military access to each other's lands. They may also dock at each other's ports, although their fleet supply range will not be extended. Furthermore, any nation in a war will be able to walk through all nations that have given access to any of the belligerents, even if those are not participating in the war.

Joining a side[edit]

After a war has started, a country usually cannot join any of the sides unless called in later. There are three exceptions to this rule. The enforce peace action allows for a country to force the attacking war leader to sign a white peace. If the attacker does not accept, the enforce will join the war on the defender's side. Another way to join a war after it has started is for a country to vassalize one of the countries involved in any of the sides. This will drag the new overlord to war as well. Finally, with Rights of Man, a great power may intervene in a war involving at least three other great powers on the side that has fewer great powers.

A way of indirectly fighting in a war is for a country to rent out condottieri to one of the countries involved.

Fighting a war[edit]

Main articles: Land warfare, Naval warfare

War may be fought on both the land and the sea. See the appropriate articles for more information.

War Exhaustion[edit]

Main article: War exhaustion

War Exhaustion represents the will of a country's population to fight. A high War Exhaustion will sap the ability of a country's armies to fight and reinforce.

Call for peace[edit]

If the warscore is substantial (66.6%+) and it has been at least 5 years since the war was declared, a country's abstracted population may call for peace. This modifier increases the nation's monthly war exhaustion, beginning at +0.01 per month, and ticks up by another +0.01 per month indefinitely. This means a call for peace will eventually start increasing a country's war exhaustion even if it has a monthly reduction, e.g. from being Defender of the Faith, having the 6th Innovative idea, or having the Kind-Hearted ruler trait. Only human players get call for peace.

Call for Peace will also occur if the country fails to submit a peace offer within 3 months of an enemy surrendering unconditionally. In this case the ticking war exhaustion begins at +0.05 per month and increases more quickly.


Warscore is the means of measuring whether a war is going in the favor of the aggressor or the defender. It is a common metric used across a number of Paradox Interactive titles, including Europa Universalis III, EUIV, Crusader Kings II and Victoria II.

The scale ranges from +100% (a complete victory for the offending side) to −100% (complete victory for the defending side).

Warscore is measured using a number of different parameters:

  • Occupied provinces
  • Battles won or lost, to a maximum of 40% in either direction.
  • Blockaded ports
  • Met war goals. A met war goal will cause war score to gradually tick up for whichever side has met it, to a maximum of 25%.

Note that both sides have symmetrical war goals. It is possible for no one to have met the goal; in particular, Show Superiority warscore won't tick if neither side has more than 10% warscore from battles, and a province goal won't tick if a third party (e.g. rebels) controls it.


Prepare For War Lyrics

Occupation is the term used to describe when a province has been successfully taken over by an enemy country. It requires the successful siege or assault of the local fortification. Upon occupation of a province, the owner of the province can no longer use the province for many purposes:

  • Regiments, ships and buildings can no longer be built in the province, and any unit or improvement building that was underway (including cores and religious or cultural conversion) is immediately halted.
  • All province income and trade power is no longer given to the owner; a portion of province income and trade power is now given to the occupier.
  • The owner can no longer use the province for a fleet base; any ships currently in the port are forced out to the adjacent sea zone. The controller does have access to these ports.
  • The province does not count for the owner for calculating naval supply, colonial range and trade range. Force limits are unaffected.
  • The controller of the province can recruit mercenaries there.
  • Occupied forts project a zone of control over unfortified land owned by countries that aren't allied to their occupier.

Transfer occupation[edit]

Countries can now give up control over occupied provinces to their allies in war. (The ‘transfer occupation’ button is located on the province screen.) This will make it possible to ensure that nations are rewarded for their participation in the war.

Administrative efficiency[edit]

Main article: Overextension#Administrative efficiency

Administrative efficiency is a country wide bonus that is unlocked at administrative technology level 17 and increases at 23 and 27, up to a total of 30%. Additionally Absolutism provides additional administrative efficiency scaling with amount, up to 40% at 100. Administrative efficiency directly reduces core creation and diplomatic annexation costs, as well as the impact of province development on overextension and warscore cost, allowing for much larger territories to be conquered at once.

Sue for peace[edit]

Peace interface, on the 'Demand tribute' tab.

This option will open the peace negotiation screen where the country will negotiate their demands, the terms of their surrender or simply a white peace. The leader of each war alliance can make peace separately with each independent country on the other side (except any that joined as part of a coalition), in which case only individual warscore against that country and its subjects is taken into account (battles only count towards overall score). This can be essential to get the desired peace deal - the overall warscore may be lower than against a single participant, so the country can get more out of the war by picking off participants one by one.

Unconditional surrender[edit]

Upon offering unconditional surrender, all of the currently unoccupied provinces will fall under enemy control and the enemy will gain 100% warscore. Armies of the country that surrendered will become exiled and unable to fight in future battles until peace is signed. For the recipient of an unconditional surrender, it will be alerted of the enemy’s surrender and from then on will be able to enforce any possible peace up to 100% warscore cost. If the recipient country does not sign peace after a couple months, they will get call for peace giving them monthly war exhaustion which increases faster than normal. The peace will be automatically accepted by the nation that surrendered. The AI does not offer unconditional surrender. They are however able to accept them.

Peace terms[edit]

Each term in a peace offer has an associated cost in warscore, Prestige gain/loss for both sides and possible aggressive expansion for anyone making sizable, selfish demands. An appropriate casus belli may modify any or all of these values, and is required to enable certain terms. A country making peace separately may only accept terms relating to itself and its subjects, not other participants in the war.

Demand Warscore Prestige Aggressive
Annex provinceProvince cost515The selected province of the country on the losing side is annexed by its current occupier, or by the country making peace if not occupied. If it is occupied, the occupier must be one of the parties to the peace. If it is not occupied, it costs 10% more warscore (20% for capitals). In a coalition war, members of the coalition may only take their own cores. AI won't accept giving away unoccupied forts, or unfortified provinces that are near forts if none of them are occupied.
Revoke coreHalf province cost10The loser revokes their core on the selected province that they don't own before the peace. Revoking cores of third parties gives them a small relations bonus towards the winner. Never costs diplomatic power.
Return coreProvince cost10The loser returns the selected core province of an existing country, and loses their core if the province is not of their primary culture.
Concede Colonial AreaSum of province costs55Requires The Cossacks. The loser cedes all provinces in the selected area to the winner's colonial subject. Furthermore, for the duration of the truce, the loser may not establish any additional colonies in the region. Can't be used against unreformed natives.
Give up claims20%2 per province0Requires Art of War. The loser revokes all claims on the selected country, who need not be involved in the war. If it's a third party, this gives them a small opinion bonus towards the winner.
Cancel subjectHalf of release nation cost50The selected subject of the loser becomes independent.
Release nation2% + sum of province costs1 per province0A new nation will be formed out of the loser's provinces with cores of that nation. The new nation will be included in the resulting truce. The new nation will have its capital's religion and culture. The loser also loses their cores except on provinces of their primary culture.
Force religionSum of province costs100Loser converts state religion and religion of their capital to that of the winner. Only possible within the same religious group.
Form Personal Union60%2030Loser becomes lesser partner of a personal union with the winner. Only available with 'Claim on Throne' and 'Restoration of Union' CBs.
Become vassalSum of province costs1 per 2 development15Loser becomes a vassal of the winner.
Become tributarySum of province costs1 per 2 developmentRequires Mandate of Heaven. Loser becomes a tributary of the winner. Only available for countries capable of making tributaries.
Pay tribute5% per loan0.5 per loan0Loser pays an immediate lump sum of ducats to the winner, measured in amount of loans. Limited to 5 loans, and results in inflation for the winner.
Concede defeat10%100A 'white peace plus', the only change being a larger gain and loss of prestige than other peace deals such as paying gold (±10 instead of ±2). Not compatible with any other terms. Can only be used between the war leaders.
Annul treaties10%10Loser cancels all treaties (including military access) with the selected country, and is not allowed to sign any new treaties with that country for a duration of 10 years. Royal marriages are unaffected.
Change government50%Loser's government type changes to that of the winner. Only available with Government Type and (unused) Revolutionary War CBs.
Transfer trade power60%10Requires Wealth of Nations. Establishes a 'Transfer Trade Power' relationship from the loser to the winner, amounting in 50% of the trade power in all trade nodes where both countries have trade power. This lasts until cancelled, which the loser can't do until the truce expires. Transfer Trade Power does not occupy a relationship slot.
Steer trade60%20Requires Rule Britannia. Establishes a 'Steer trade power Steer Trade' relationship from the loser to the winner, forcing them to use their merchants to steer trade towards the winner.
Humiliate40%50Winner gains 30 power projection, loser loses 30 power projection. Note that the power projection bonus from humiliating any one rival caps out at 30; and doesn't stack, instead refreshing the bonus. Only available if the loser is the winner's rival.
Show strength100%00Winner gains 30 power projection plus 100 of each monarch power, loser loses 30 power projection and 20 prestige. Note that the power projection bonus from humiliating any one rival caps out at 30; and doesn't stack, instead refreshing the bonus. Only available with the 'Humiliate Rival' casus belli.
War reparations10%20Requires Art of War. The losing party is forced to pay 10% of their income to the winning party as war reparations. This lasts for 10 years.
Revoke elector60%525Revoke elector title. Not available if Common Sense is enabled – use the diplomatic interaction instead.
Force migrations100%20Requires Conquest of Paradise. Force a primitive nation to migrate elsewhere. Only possible when the nation is small enough.
Enforced military access15%00Force a nation to give military access until truce expires.
Enforced fleet basing rights25%00Force a nation to give fleet basing rights until truce expires.
Enforce rebel demands50%20Force a nation to accept the rebels' demands. Only works with the 'Support Rebels' casus belli (requires Art of War).
Religious Supremacy50%370Attacker's religion becomes the official religion of the Holy Roman Empire. Available only with the 'Religious League' casus belli (requires Art of War).
Claim Mandate of Heaven50%250Attacker becomes the Emperor of China. Available only with the 'Take Mandate of Heaven' casus belli (requires Mandate of Heaven).
Dismantle the Revolution50%370Defender stops being the revolution target and becomes a monarchy. Available only with the 'Crush the Revolution' casus belli.

Unjustified demands[edit]

Peace terms that are not part of the wargoal will cost 3 per development of affected provinces:

  • Annex province
  • Cancel vassal
  • Release nation
  • Force vassalization

The diplomatic power cost of unjustified demands can be reduced by:

  • Full Influence
  • Creek traditions
  • Kikuchi traditions
  • Siberian traditions
  • Barbary Corsair idea 6: Heirs of Al-Andalus
  • Moravian idea 7: Legacy of Great Moravia
  • Nagpuri idea 7: Unjustified Expansion
  • Piratical ambition
  • Imagawa idea 7: March to Kyoto
  • Despotic Monarchy: −10%
  • Ottoman Government: −10%
  • Demanding provinces from a rival: −33% for annexing provinces only
  • Having a claim: −10%

Note that forming a separate peace can incur a diplomatic power cost, since there is effectively no casus belli when not negotiating with the war leader.

Distribution of spoils[edit]

Shows distribute spoils in game.

How To Get Favors Eu4

Spoils of war are distributed between its participants with prestige and money going to the belligerents of the war based on their war contribution rather than only to the war leader. For example, if Spain and France fight in a war against Great Britain and France gets 70% war contribution and Spain 30% then the prestige and money will be divided so that 70% goes to France and 30% goes to Spain.


Once a peace deal is accepted, it results in a state of truce between every country on the offering side and every country on the accepting side. Specifically, when a country other than a war leader accepts peace, or offers a peace deal the other side's war leader accepted, it enters truce with every other country it fought in the war, but countries on its original side are not affected. A country cannot embargo or join a coalition against a country it has a truce with. It can still declare or join a war with the country with a truce, but with the following consequences:Breaking a truce will result in the following penalties:

Ideas Stability War exhaustion Aggressive expansion
Normal-5+5 war exhaustion.-50
Full Diplomacy-3+3 war exhaustion.-30

These stack with the penalties for other reasons. So attacking without a CB and without full diplomacy results in -7 stability, +7 war exhaustion and -70 aggressive expansion. As seen above, breaking a truce has very negative effects when declaring war or joining an offensive war against a country with whom a truce exists. The AI has -1000 reasons to join an offensive war if they have a truce with the defender and appears to never declare war or join as an ally in an offensive war if that would break a truce. Joining defensive wars does not give a penalty.The duration of the truce depends on the amount of warscore that was used to demand or offer tribute in the peace deal. The formula is

so a white peace will result in a 5-year truce, whereas a full annexation at 100% war score will produce a 15-year truce. When a country is released in a peace deal, it starts with a 5-year truce with both the releasing nation and the opposing war leader.


An example of revanchism from an EUIV developer diary.

Revanchism is a mechanic that helps prevent a 'death spiral' after losing a war where a country would go bankrupt, lose manpower and have huge revolts, followed by other countries declaring war as well, leading the nation to ruin. Revanchism is gained from losing provinces in a war and scales in direct correspondence to the war score taken in a peace deal, with a max of 100% revanchism at 100% warscore. Once at 100% revanchism it takes 20 years for the effect to fully wear off, lasting longer than the resulting truce that caps out at 15 years for 100% warscore. Releasing nations and returning cores does not grant revanchism.

With maximum revanchism of 100% (from having 100% warscore worth taken in a peace deal), a country gets the following modifiers: [1]

+50%National tax modifier
+25%Fort defense
+50%Manpower recovery speed
+1%Yearly army tradition
+1%Yearly navy tradition
−5National unrest
−1%Interest per annum
+10Yearly horde unity

These modifiers scale linearly with revanchism from 0% to 100%

Note that revanchism caps out at 100%, even if a peace deal worth more than 100% warscore in total was taken (such as in multiplayer that allows peace deals over 100% warscore or from multiple peace deals).

Negotiating peace[edit]

Human players are largely free to accept or refuse any peace deal. However, as with other diplomatic actions, the AI will accept a peace deal if and only if it has more positive than negative reasons to do so.


The warscore is of primary importance. Each point of warscore will give +1 reason for the AI to accept a peace deal, whereas each warscore cost of the peace terms will give −1 reason for the AI to accept a peace deal.

Demands exceeding warscore will give additional negative reasons for the AI to accept the peace deal, up to −100 at 99% warscore and lower. Demands exceeding 100% warscore will give −1000 reasons (unreasonable demands, not to be confused with Unjustified demand). Individual demands that would cost over 100% warscore, such as vassalizing a country that is too large, can't be selected.

If one side of the war has 100% warscore, the AI is forced to accept any peace offer of 100% or less warscore, including tribute to them. This does not apply to losing human players.

Regardless of warscore, the AI may refuse peace deals that contain terms that they do not desire; for example, provinces they will be unable to core. Such offers cannot be submitted (the 'Send Demand' button is greyed out). The only exception is stated above, where the AI is forced to take a province they are unable to core if the other side has more than 100% warscore.

Province cost[edit]

Each province that changes control in a peace deal requires a corresponding warscore cost. The factors that influence each province's warscore cost are:

Base5 per province.
Development1 per development, cap at 30
Trade power0.2 per base trade power (before modifiers applied)
Capital+2% of (base + development) cost if the province is a capital
Local autonomy−0.33% per percentage point
Size of nation−1% per 15 development of nation (owner)
Administrative efficiency−1% per point of of the annexing country's administrative efficiency
Religious Wars−25% if province is not attacker's religion (Age of Reformation ability)

The local autonomy, size of nation and administration efficiency factors are applied multiplicatively.

The following ideas reduce province warscore cost:

  • Diplomatic idea 6: Flexible Negotiation
  • Asturian idea 1: Reconquista
  • Desmondian idea 4: The Munster Ambition
  • Oda idea 2: Tenka Fubu
  • Ito idea 4: Anti-Shugo Movement
  • Qara Qoyunlu 2: Governor of Azerbaijan

War enthusiasm[edit]

Eu4 favor system

Other factors also give reasons for the AI to accept or refuse a peace deal. These are summed up as war enthusiasm in the war screen. Positive War Enthusiasm is applied as negative reasons for that country to accept peace deals.

  • Length of war: +45 at start of war, decays by −0.75 at the start of each calendar month thereafter (5 years until it becomes negative).
  • Casus belli 'Religious League' and 'Crush the Revolution': +50
  • Casus belli 'Coalition': +30 for attackers
  • Relative strength of alliances: −20 to +20 for war leader only
  • Ally in war: +10 for allies called in by war leader
  • Military strength: −20 to +20, depending on proportion of manpower and land force limit that is filled, as well as battles lost or won
  • Recent gains: −20 to +20 for war leader only.
  • Hold their own capital: +5
  • War exhaustion: −1 per point of war exhaustion
  • Occupied and besieged provinces: scales linearly with base tax of provinces affected, up to −20 for full besiegement, and −40 for full occupation. The formula is roughly
Colonies and distant overseas provinces are ignored in the calculation above.
  • Revolts in country: depends on the size of all rebellions relative to current military strength. The formula is
with the final number rounded to the nearest integer and capped at −20.

If war enthusiasm is between 0 and 20 it's classified medium, below it is low and above it is high.

Stability hit[edit]

If a player refuses a peace offer that entails demands for less than 50% of the current warscore, and the warscore itself is higher than 50%, the declining party takes a −1 hit to stability. When a player is already at −3 stability, any qualifying offer is automatically accepted on behalf of the player.

The AI will almost never refuse an offer that would result in a stability hit, so its main area of application is multiplayer games, where this mechanic aims to prevent players from unreasonably dragging out lost wars to harm his/her opponents (by deliberately causing war exhaustion to rise or rebels to spawn).

However, if you demand a province in an area where no fort is taken, the AI will refuse it, resulting in −1stability and −5prestige. If the AI already is at −3 stability, they will instead lose −10 prestige.


  1. See in /Europa Universalis IV/common/static_modifiers/00_static_modifiers.txt under recovery_motivation(Static modifiers#Revanchism).
Land warfareArmy • Land units • Discipline • Manpower
Naval warfareNavy • Naval units • Sailors
Other conceptsCasus belli • War exhaustion • Military tradition • Leaders • Alliance
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