Eu4 Diplomatic Relations Slot

Disclosure: This guide is inspired by one of the posts I read on Reddit and realized that despite it’s steep learning curve, there isn’t a central hub for EU4 guides. Here is my attempt to help out the newer players who want to try their hand at EU4.

• Eu4 Diplomatic Relations Slot Definition
• Eu4 Diplomatic Relations Slot Strategy
• Eu4 Diplomatic Relations Slot Machine
• Eu4 Diplomatic Relations Slots

• EU4 doesn't support dynamic trade map, and doesn't allow cycles, so any trade map will require compromises. The mod adds Panama to Mexico and Patagonia to Lima link, and (to prevent cycles) removes Philippines to Panama and Mexico to Panama links. This lets Asian powers enjoy New World trade from at least Pacific parts of the New World.
• Diplomatic relations will be reduced by the aggressive expansion penalty. The negative modifier will decay by a base of +2 per year, further increased by bonuses to improve relations. Attitudes towards the aggressor may change to outraged, regardless of the original attitude or relation.
• Diplomatic rulers will try to maintain good relations with neighbors, and their diplomats will be preoccupied with improving relations rather than fabricating claims on their neighbors. They will try to expand through diplomatic vassalization if possible, often breaking alliances with larger nations just to free up relation slots for that purpose.

One of the best things I like about EU4 is it’s endless replayability. You can not only play different nations, but you can play the same nation in many different ways. You can min-max and live on the edge or you can sit back, relax and play at your own pace. And so, I have decided to split the guide into two versions- a Guide to Assertive Austria (for minmaxing play style) and a Guide to Amicable Austria (for more casual play style). Remember, there is no right or wrong way to play this game. Just have fun!

Austria is one of the few nations where you will use diplomacy more than war to get a solid base for world domination. This guide will help you set up the first couple of months and fulfill short term objectives. Diplomacy has to be timed fairly well, as once nations fill their relationship slots its harder to get alliances and royal marriages (RM). I have laid out each step you will take for the first couple of months. After that, I will lay out the next objectives in more broad terms. I wish I could give you a longer step by step guide, but the RNG in game will dictate how you play to some extent. Even the steps here might change a bit if some nations decide to send you alliance/RM offers.

Guide to Assertive Austria

Before 1500

Vassalization can occur militarily by forcing it upon a defeated enemy in a war. Diplomatic vassalage can occur if a military alliance exists and relations are high (above 190). Vassals cannot declare war, and fabricate claims that either they or their overlord deems as 'Vital Interest'. Vassals with over.

Primary Objective: Force PU on Bohemia and Hungary

Secondary Objective: Prevent Shadow Kingdom

1. If Bohemia, Poland, and/or Burgundy rival you, you need to restart until they don’t. Its not save scum if you don’t start the game.
2. Get the level 2 diplo rep advisor (scripted, half price). Get a cheap millitary advisor, preferably morale, but discipline or fort defense works too. Get a level 1 admin advisor (tax or inflation guys are nice). Set military focus for now.
3. Rival Ottomans and Venice leaving one slot open for a future Bohemia. You will use this open slot for whoever you attack next (bohemia, hungary, papal state, venice etc).
4. Set troop maintenance for 3/4ths readiness. Turn off fleet maintenance.
5. Mothball all your forts.
6. Play with you estates the usual way to get extra monarch points. Clergy: Recruit theologian/Send emissary to Pope/Demand Admin/Make contribution. Nobility: Grant General/Demand Mil. Burgers: Demand Diplo.
7. Spend all diplo on developing Tirol gold mine. Move the 7 stack to Linz. Sail all ships to Straits of Otranto. Move your merchant from Ragusa to Wien. Once you get a cardinal, invest in becoming the papal controller.
8. Royal Marry (RM) Burgundy and ally Poland. Austria starts with 2 diplomats so we will juggle them around cooldown times. Don’t ally burgundy because you don’t want to be called into their defensive wars.
9. RM Bohemia. Remember, don’t ally them.
10. Embargo Venice
11. Ally Papal State (we ally them now to use up one of their relationship slots)
12. Ally Milan (they will help in your war against Venice and maybe even the Popeman)
13. RM Hungary. Again, don’t ally them, you will go against them in few years.
14. Sell 2 transports for 30 to Ferrera
15. Embargo Ottomans
16. Sell 3 galleys to Ragusa for peanuts. They’re the only ones who’ll buy them.
17. Sell your trade ship to Urbino for 20.
18. RM Poland
19. Sell 2 transports to Lucca for 30
20. Insult Venice
21. Sell 2 transports to Sienna for 30 (should have no ships left).
22. RM Milan
23. Usually you’re going to have to RM Burgundy/Bohemia again because they’re usually rivaling one of your allies. They’ll stick with you after the second time. You should be 1 above your relationship limit.
24. Build spy network on Papal state and improve relations with the electors.
25. When you get to idea groups, go for Diplomatic, then Religious.
26. For Age of Discovery abilities, go for reduced aggressive expansion (AE) and free war taxes.

Bohemia PU

Now you open up the diplomacy screen for Bohemia, go to speed 4 or 5 and stare at it till you see a von Habsburg as a ruler. There is some RNG element to it and you might need to save scum if you really want Bohemia under PU. Although its really handy, its not end of the world if you don’t get the PU right now (you can get PU with another event after 1500). If you do see a von Habsburg at the throne, you need to immediately pause the game and click on claim throne. Build your force limit to 25 with mercs, raise army and fort maintenance. After a month when you can send the diplomat again, rival Bohemia and declare war on the same day. Sometimes, you will lose the restoration of union CB after rivaling, so don’t dawdle. Go to war and win it. This could be a long drawn out war depending on who Bohemia allies, so play smart. Siege their capital and try to use the terrain to your advantage in battles. You will need to take some loans. You need 84% war score to enforce the PU.

The First Papal War

Next you need to attack the Popeman. This is to prevent the Shadow Kingdom. The event Rein in Northern Italy is your friend here. You will need to own Ancona, Romagna, Umbria, and Roma along with Urbino to prevent Shadow Kingdom. This is a 2 war process. Dissolve your alliance and break truce (if you wait till truce is over, papal state might have a stronger ally. Though you can save scum and take that chance). Get Ancona, Urbino and Romagna (and Umbria if you can) in the first war. Milan is unlikely to help and Bohemia might still have more than 50% liberty desire, so you will be all alone in this war. Popeman will likely have Genoa/Mantua as allies, making the war fairly quick. I have to emphasize here that preventing Shadow Kingdom is not utterly necessary. Yes its nice to have that extra Imperial land for Imperial Authority (IA) points generation. But if Papal State is allied to Castile/Aragon/France, the war will drag on for a long time and you might want to consider just letting Northern Italy go for now. You can always conquer it later. Build spy network on Venice while at war here.

Hungary PU

Use the Restoration of Union CB on Hungary either via Claim throne or event or the mission (it will depend if Hungary has annexed Wallachia yet or not). Rival them and declare war on the same day. They might have Bosnia or Serbia as allies. This shouldn’t be a very tough war. You will need 60% war score to enforce the PU.

Venetian War

This war is again part of the Shadow Kingdom prevention. You need to take Brescia, Treviso, Friuli, and Verona in this war. Milan will help you out as they want Brescia, you can give it to them. Get this war done. You will have a lot of AE at this point, so keep your diplomats busy with improving relations.

The Second Papal War

Eu4 Diplomatic Relations Slot Definition

Finally you attack the Popeman one last time to take what is left of it. Ideally, you want to declare war at the day your truce expires. Pray to RNGesus that Popeman doesn’t yet have a strong ally who is willing to protect them. This really is luck based. If France comes to their aid, there is slim chance you will be able to complete the war before 1490, when the Shadow Kingdom event fires. If you do get lucky and Popeman has weak allies, get the war done quick and take Umbria and Rome. Take the Reign in Northern Italy decision which will end the Shadow Kingdom event for good. Start coring Umbria, but don’t core Rome. Once you own Rome as a catholic nation, there is a modifier called Occupation of Rome which gives -1 diplo reputation and decrease in Papal authority, both bad when you are playing as Austria. Wait a few days and an event will fire where Popeman asks for Rome back. Give it back and start improving relations to gain papal authority.

Take a breath

You have done it! Now you can relax… for more or less 10 years. Get your manpower back. Get your finances back on track. You are going to need it. Bank a bit of admin points, you might have to no CB some heretics.

Next Big Objective: Deal with Reformation

There are a number of guides to dealing with Reformation and keeping HRE Catholic. I will refer you to one of them (personally I think Reman’s video is excellent). You will have to no CB someone, but you should have completed the diplomatic idea group by now which gives you lowered impact on stability from diplomatic actions (still -3 stab if you no CB a free city though).

1550 and beyond

Your main goal is to get more IA. Keep annexing new lands to HRE, releasing new small nations when you can. And make sure no heretic religion survives in HRE. If England goes Anglican, it will be a constant pain but you can’t do too much about it. Eventually revoke the privilegia and feed all the land to your vassals.

Guide to Amicable Austria

Well, you aren’t going to be amicable really. But you won’t rack up AE like the last guide. And you will solely focus on IA and more event based PUs with Bohemia, Hungary, and Spain/Castile.

Primary Objective: Force PU on Bohemia

Secondary Objective: Get back the Imperial land

Step 1 through 10 are mostly the same as Assertive Austria except don’t turn off fleet maintenance and send your trade ship to protect trade in Venice.

1. If Bohemia, Poland, and/or Burgundy rival you, you need to restart until they don’t.
2. Get the level 2 diplo rep advisor (scripted, half price). Get a cheap millitary advisor, preferably morale, but discipline or fort defense works too. Get a level 1 admin advisor (tax or inflation guys are nice). Set military focus for now.
3. Rival Ottomans and Venice leaving one slot open for a future Bohemia. You will use this open slot for whoever you attack next (bohemia, hungary, papal state, venice etc).
4. Set troop maintenance for 3/4ths readiness.
   
5. Mothball all your forts.
6. Play with you estates the usual way to get extra monarch points. Clergy: Recruit theologian/Send emissary to Pope/Demand Admin/Make contribution. Nobility: Grant General/Demand Mil. Burgers: Demand Diplo.
7. Spend all diplo on developing Tirol gold mine. Move the 7 stack to Linz. Sail all ships to Straits of Otranto. Send trade ship to protect trade in Ragusa. Move your merchant from Ragusa to Wien. Once you get a cardinal, invest in becoming the papal controller.
8. Royal Marry (RM) Burgundy and ally Poland. Austria starts with 2 diplomats so we will juggle them around cooldown times. Don’t ally burgundy because you don’t want to be called into their defensive wars.
9. RM Bohemia. Remember, don’t ally them.
10. Embargo Venice
11. RM Castile. Don’t ally yet, they might go to a succession war with Aragon over Navarra where they are the defender. You don’t want to be called into it.
12. Ally Hungary.
13. Sell your transports to Ferrara, Lucca and Siena. And your galleys to Ragusa.
14. RM Poland.
15. Insult Venice.
16. You might have to RM Burgundy or Bohemia again.
17. Build spy network on Venice and improve relations with the electors.
18. Ally Castile when they are done with the Navarran succession war.
19. Idea groups are again Diplomatic, then Religious.
20. For Age of Discovery abilities, go for reduced AE and transfer subject.

Eu4 Diplomatic Relations Slot Strategy

Bohemia PU is same as with Assertive Austria.

[Now you open up the diplomacy screen for Bohemia, go to speed 4 or 5 and stare at it till you see a von Habsburg as a ruler. There is some RNG element to it and you might need to save scum if you really want Bohemia under PU. Although its really handy, its not end of the world if you don’t get the PU right now (you can get PU with another event after 1500). If you do see a von Habsburg at the throne, you need to immediately pause the game and click on claim throne. Build your force limit to 25 with mercs, raise army and fort maintenance. After a month when you can send the diplomat again, rival Bohemia and declare war on the same day. Sometimes, you will lose the restoration of union CB after rivaling, so don’t dawdle. Go to war and win it. This could be a long drawn out war depending on who Bohemia allies, so play smart. Siege their capital and try to use the terrain to your advantage in battles. You will need to take some loans. You need 84% war score to enforce the PU.]

Pay off your loans; improve relations with Bohemia and get your manpower up.

Eu4 Diplomatic Relations Slot Machine

Venetian War

When you are ready, declare on Venice and take Treviso, Verona, and humiliate them.

Eu4 Diplomatic Relations Slots

Hungary PU

If you get the Hungary event with Restoration of Union CB or you can click on the mission. Do it and get that PU. You can dissolve the alliance and wait for truce to expire. No need to hurry on this. You can call Poland in as well.

Next steps are up to you. If you don’t have Burgundian Inheritance yet, you can declare on them and release its subjects which will add to the IA. You can also attack Denmark to demand Holstein, and while there snag Norway as a subject of your own (you will need the Transfer subject ability from age of discovery though). Also, get your rightful Imperial lands back from Northern Italy.

I would still recommend crushing the reformation as the religious league wars are a massive waste of time and resources. Next whittle down France with the help of Castile/Spain, flex all your might against Ottomans and you will have smooth sailing from here on out.

Here is the video tutorial.