I'm really, really loving my Bohemian run of Europa Universalis IV. Maybe even more than my Portugal run, though I've been surprised by just how different the games are. Portugal was incredibly expansive, filled with exploration and traveling over vast distances and building long trade chains to funnel exotic goods into Sevilla. Bohemia is exclusively focused on Europe, and especially in the Holy Roman Empire and its immediate neighbors; despite the smaller geographical footprint, though, there's a significantly larger number of nations involved, with webs of alliances and rivalries and regional politics. I'm totally ignoring some systems and mostly ignoring others, while mastering others I never encountered while playing as Portugal.
I'm not going to try and give a chronological recap of my game so far. Instead I'll try and cover the areas I've focused on. In no particular order:
Actually, let's rotate clockwise, starting from about 2 o'clock. My first Personal Union was with Poland. I had allied Muscovy and the Ottomans to take them over, but Muscovy never was willing to join due to their crippling debt, and the Ottomans weren't very helpful either, but eventually they became willing. When my first monarch died, I was shocked to read that I had directly inherited the Polish lands. From reading the wiki I didn't think that was possible, since their development was so large: I had already started the lengthy annexation project and was about 20-25% of the way through. On the one hand I wish I hadn't "wasted" all that diplomatic mana, on the other hand I was happy to save the other 75-80%.
Since this was unexpected, it pushed me over my Governing Capacity, especially on top of the Burgundy Inheritance. That initially freaked me out, as I've been careful to keep near but not over the cap. It turns out to not be a huge deal, though. The biggest issue is slowing down your Aggressive Expansion decay, but that isn't too painful and is more of a long-term thing to address. It did mean that I needed to start prioritizing building Courthouses and State Houses in addition to the other things I wanted to spend ducats on. When I finally got some headroom in my Governing Capacity, I was able to begin Stating areas of Poland to get lower autonomy and more money and resources.
The other wrinkle has been culture. Bohemia starts off with Czech primary culture, which is in the Western Slavic group along with Polish, Silesian and other cultures in that area. So it's pretty natural to expand east and absorb them, since other cultures in the same group have lower penalties, and once you rise to Empire (more on that later) you automatically accept all cultures in the same group. From reading an online strategy guide, though, folks recommended switching to a German culture, ideally something like Saxon. There are a lot more subcultures within the Germanic group than within the West Slavic group, so you need to promote a lot fewer cultures of West Slavic than you would of German. Being Saxon also allows you to form other nations, including Prussia. They advise doing this early on while your empire is still small, because it can become impossibly expensive to switch later. Changing culture is a very very long process, with a single province easily taking a decade to switch and eating a lot of diplomatic mana.
I eventually spread enough Saxon culture to be able to switch primary. It's been all right. At this point in the game I think I would actually still be better off with Czech culture, because I haven't been directly taking very much HRE territory (more on that later), while I have directly taken almost all West Slavic provinces. But I can see how that would shift in the future. It's also kind of interesting since my primary culture is now Saxon but my ruler's dynasty is still Czech, so there are some occasional events that pop up about the tension that creates.
Lithuania has remained in Personal Union with me. I'm really glad that they hadn't merged with Poland prior to me creating our union; a single Commonwealth would have been a lot more powerful, had more Liberty Desire and made a far more abrupt impact when integrated. Lithuania is still plenty powerful on its own, does a good job at looking over its vast territory, and serves as a helpful buffer state against Muscovy. One minor annoyance with all my PUs is that they grant Orthodox Autonomy rather than convert the provinces to Protestant. I sometimes have spare Missionaries and would happily do it myself, but can't. Once I do eventually take over the territories I then have a bunch I need to do all at once. Not the end of the world, especially as my empire grows enough that it doesn't affect Religious Unity too much, just a minor annoyance.
Speaking of minor annoyances: the Teutonic Order was a thorn in my side for a while, but actually a kind of good thorn. I think I alluded to this near the end of my last post, but they were a Catholic nation, on the opposite side of Europe from the revolving-door Catholic Defender of the Faith, so any time I wanted to reset the DoF I'd declare on the TO, beat them up, take all their money and end the war before armies from Portugal or Spain or England or France could reach me. The TO did eventually join the HRE, which made things a little more tricky but just meant I needed to get an appropriate Casus Belli before attacking. I was nervous when they eventually flipped to Protestant as I was concerned they might form Prussia and I wanted to keep that door open for myself; but from some online research I saw that I had already taken away the provinces they needed for that, so they can just chill out in Malbork Castle indefinitely.
And speaking of blocking country formations! As I mentioned before, I initially allied Muscovy, but they were completely useless allies. Once I made the union with Lithuania, Muscovy broke our alliance and became extremely hostile, due to wanting Lithuanian land. I wasn't too concerned about this; the Bohemian-Polish-Lithuanian-Hungarian union was beefy enough to take on Muscovy, plus I had other allies in my pocket. But looking to the long-term I wanted to defang Muscovy before they would have a chance to form Russia.
Russia usually emerges as the end boss in Europa Universalis games. Way back in EU3, my Mecklenberg juggernaut was almost brought down at the end when swarms of Russians invaded over the Mongolian steppes into my wealthy Asian holdings. In my EU4 Portugal game I blocked them from reaching the Pacific, but then had to defend those lands against an endless stream of bodies. Russia tends to not be a threat for much of the game since they aren't strategically located, but once fully-grown they have a functionally infinite number of soldiers and reserves, territory so vast it can never be fully occupied, and punishing attrition that will bleed enemies dry before a single shot is fired. (Which, to be fair, is pretty realistic!)
So, to be kind to the 1750s version of myself, I wanted to keep Muscovy from ever creating Russia. Once again I consulted the wiki. I saw that they had already taken all of the provinces they needed to form the nation and were just waiting on the right Administrative Technology. Looking over what to take from them, I eventually settled on Novogrod, which was very close to the Lithuanian border. I think I might have called the Ottomans in on this war if I remember right, and they kept Muscovy busy in the south while I took their lands in the north.
After this I stopped worrying so much about Muscovy/Russia, but several decades later, my Nobility Estate made an interesting proposal during a Diet to take two other provinces in modern-day Estonia. The provinces by themselves weren't exciting, but Moscow didn't have any strong allies and was behind me in tech, and I needed to burn off some Germanic Aggressive Expansion, so I liked the idea of pounding the east for a bit. My big prize this time was Moskva itself, mostly because of its awesome Great Project. They have two: the Kremlin isn't very interesting to me since it requires Slavic culture, but Saint Basil's Cathedral looks awesome: fully upgraded, it gives a beefy +10% Loyalty Equilibrium to all Estates, along with some other goodies like cheaper advisors and higher Tolerance of the True Faith.
This was kind of a weird war, in that I don't think I fought a single battle the whole time. Muscovy supposedly had like 70k troops, versus around 45k I directly controlled and maybe 120k for my entire side. They never once appeared, though. Maybe they were trying to lure me into Siberia.
Continuing clockwise: much like Muscovy, the Ottomans were early allies of mine that turned into rivals, in this case after they helped me enforce the union with Hungary and so we ended up with competing claims over the Balkans. A big chunk of Bohemia's Mission Tree involves this area, with some fun and creative missions like building up a system of forts, then retaking provinces in the Balkans and eventually removing the Turks altogether. That's pretty much how this went down. After losing Muscovy and Ottomans, I picked up Venice and Mamluks as my next allies. Venice doesn't have a huge army, but they have possibly the biggest navy at this point of the game, had many naval bases near the Black Sea, and were eager to take on the Ottomans. The Mamluks were powerful in northeast Africa and the near Middle East and had ambitions of their own against the Ottomans.
This was a big campaign that involved multiple wars. I think that the first time I pretty much just took Constantinople, along with provinces in, hm, I think Silestria for a mission. Taking Constantinople is expensive but really important, as for all future wars it is a chokepoint that separates Ottoman armies in the Balkans from those in Anatolia, letting you easily divide and conquer them. In the second war I took Greece and the coastal provinces, then in a final third war I took the few remaining inland provinces, while avoiding personally encroaching onto Anatolia.
I had a lot of extra warscore for this third war, since I didn't need many more provinces and by this point was easily thrashing them. I ended up forcing the Ottomans to release a lot of nations, mostly along the southeast coast of the Black Sea and extending into Armenia and Azerbaijan. This will be a recurring theme for this post, which I'll definitely write more about later: during my Portugal game I always wondered what the point was of releasing a nation instead of taking the provinces directly, while in Bohemia I've probably liberated more provinces than I've conquered. Anyways, I tend to think of peace negotiations as being basically a shopping trip: spending war score to get the most bang for my buck. I think it took me over half an hour to figure out how to end this war, and I used one and a half sheets of notebook paper to plan things out.
There are a lot of releasable countries. My long-term scheme (not yet implemented) is to extend the Holy Roman Empire all across Europe, from the Atlantic Sea to the Black Sea. That means creating small Christian nations that I can force into it. Ideally small Protestant nations. Thanks to the Orthodox Autonomy, lots of these provinces are still Orthodox and will take that faith when liberated; then, you can "Force Religion" in a future war (or, I suppose, as a vassal) to switch their denomination.
So, what I was trying to do was to make as many small Christian countries as I could, which meant pulling up the peace negotiations, clicking "Release Nation", selecting a potential candidate, seeing which provinces it would get, seeing how much War Score they cost, closing the negotiation window, clicking into the provinces, checking their religion, checking to see whether they were European or Asian, jotting those values down in my notebook, and then repeating for the 30 or so releasable nations. Oh, I also wanted to see if they were contiguous to me, or across a sea zone, or could be contiguous to another nation I was releasing.
I finally did this, getting all those nations released. It's kind of fun to see how quickly baby nations start up their own Game of Thrones: in almost no time they were allying and rivaling one another. Which makes sense, they aren't nearly big enough to vie with the Ottomans or myself.
In the time since then, I've already intervened in a couple of wars (thanks to a "Babbling Buffoon" warning) between them, in the process smacking around Muscovy some more and enforcing quite a few of them to embrace Protestantism. That will be an interesting region in another decade or two.
The Mamluks have been good allies to me, as we're both very powerful but at least so far content to be in our separate spheres of influence. I wouldn't be surprised if we start butting heads in another century or so. From what I've read online, when the player (me) intervenes to thwart the typical mega-powerful lucky nations, another AI nation ends up blobbing in its place: if Russia never forms, the Polish-Lithuanian Commonwealth usually gets huge, and if the Ottomans don't get big, the Mamluks do.
Right now I have very little visibility into the world east of the Caspian Sea, with no lines of site on India, China or anywhere in the Pacific. I can see the Mughals, who seem like they may be the main power in the Persian area. I'm really looking forward to getting visibility into Asia, at the very least so I can open diplomacy with any major powers out there, and who knows, late in the game I might want to hop back into the global trade realm.
Moving back up the Adriatic Sea: my third Personal Union junior partner has been Hungary. They were the problem child for a long time: they were large and angry after I forced them into the union, and were disloyal even without forcing religion on them. By this point in the game I'd accrued a lot of Aggressive Expansion and a lot of countries were very mad at me, so I think at one point Muscovy, France, Castile and England were all supporting Hungary's independence, which in turn made them so disloyal that there was no mathematical way to make them loyal again.
I stumbled across the solution: war! Apparently when you have a truce with someone, they can't support your subjects' independence. After peeling off Muscovy, my wars against the Catholic Defender of Faith managed to knock out the other supporters. Once those were gone, Hungary flipped to fully loyal (0% liberty desire). I finally enforced religion, then immediately started paying a stipend to support them (keeping LD below 50%) until they were back in the clear.
Collectively, Hungary and Lithuania are amazing. Big armies, decently smart AI, incredibly loyal. They more than pull their weight in our wars.
Venice has been an interesting one. As noted before, I recruited them as allies after rivaling the Ottomans, and we had close to a century of good cooperation, with my army and their navy acting as a hammer and anvil to smash the Saracens into the Bosporus. While Venice and I are geographically close, we haven't been competing much, with me focused on northernish Germany and Eastern Europe while they focus on Italy. Again, aggressive expansion proved my undoing, and they eventually broke our alliance.
I'm jumping way ahead in time here, but my most recent major event before writing this point was a shooting war against Venice. I'd been eyeing two Imperial Provinces that Venice owned, one in Corsica and the other on the north Adriatic coast. The problem was they were allied with France, and Spain was Defender of the Faith, so it would be a very challenging war. But I was delighted to see that Spain attacked France and pulled Venice in as an ally. Now I could declare on Venice: I'd still need to contend with France, but not Spain, and France and Venice already had their hands full with Spain and its allies.
France is another nation in this game that's typically a major power but has been relatively subdued so far in my play-through. Since I won the Burgundian Inheritance and kept it all I've blocked out their typical eastward expansion. Savoy has been pretty powerful in gobbling up the old lands around Genoa, and Savoy is allied with France. So while France has consolidated it hasn't really expanded like normal.
In this war, Spain had already started sieging the south of France. Paris was just a Level 1 fort, two provinces away from the front, so I marched in a small army and captured it in a few months. The rest of the nation was much beefier new Level 4 Forts, which kept me occupied for a while. There was a bit of the large tactical dance and fakery that I love in Europa Universalis, with large armies positioning and forcing each other to move without committing to battle. A few times I initiated a siege to draw back forces from Italy, then withdrew behind my safe lines, picked off stragglers, then settled in for longer stays after the armies retreated.
My other major goal of this war was, yes, to militarily convert provinces to Protestantism: specifically, Sienna (who Austria had made a Free City) and, hm, I think Urbino or something. But they were below Venice, who had most of the peninsula north of Rome. Again, lots of Level 4 Forts, and the Alps always make that area hard to navigate. Venice itself fell pretty easily, as it was just a Level 1 Fort, and their navy left for long enough for me to cross over. (I definitely called the Mamluks into this war, and they have a surprisingly beefy navy.)
Speaking of navies: for probably the first hundred years or so I didn't have one. Bohemia is landlocked, and even after I started getting a handful of coastal Polish provinces I didn't really care about booting it up. I'll never be a great maritime power, but I do have a moderate fleet now that probably punches above its weight. At first I just got Light Ships to boost Trade Power in some key coastal Centers of Trade, but in the last few decades I also bought a chunk of Heavy Ships along with a handful of Transports. My main goal here is to avoid the -2 penalty when sieging coastal forts, and I can usually squeeze some War Score out of sinking a few enemy boats when fighting small nations. Venice has like 120 ships though, so I definitely can't face them in a fight.
I did get to do my first naval invasion of the game, and it may end up being my last: Corsica. Transporting troops in this way takes about a month, and I was nervously watching the main Venetian fleet on the other side of Italy, delighted when we finally landed.
As often happens with large wars in EU, it felt like things ground on slowly for a long time, then everything quickly wrapped up. France was unwilling to even accept a white peace even after I had captured their capital and several forts. I think the AI is extremely reluctant to sign peace within a year of a war starting. Before long, though, they were close to 100% occupied: maybe 70% by me, 20% by Spain with a single fort and a handful of provinces left. They still had a large army, but it was off conquering Spanish land in Naples.
I had initially declared this war with the Imperial Ban (more on that later), and I realized that I couldn't take arbitrary provinces from them. Which is fine, I wasn't expecting to; I did have my eye on Caen and some other Centers of Trade in the English Channel, but it wasn't a requirement. My main goal with France was to get rich, taking lots of money and war reparations from them. I think I cleared over 2k ducats, which was enough to get to Level 2 of a Great Project. I also canceled all of their claims on me (but of course they made another claim just a few months later). And once again I released a nation. Because French land is so rich / high dev I wasn't able to free up the vast territory that the Ottomans had given up, but still, by this point in the game I'm having a big blast just breaking people up.
I think my overall warscore prior to peace-ing out France was like 67%; after doing it, it jumped to 99%. I was a little surprised; usually warscore drops after eliminating an enemy, since you no longer get credit for their occupied provinces. But this also removed their substantial armies from the calculation, and by now I had solely occupied all Venetian land. So this ended up being an even richer peace than I had expected: the two provinces I wanted, maximum money, and I ended up releasing, hm, I think four or so nations: Dalmatia along the eastern Adriatic and a bunch of inland Italian states. Again, long-term my plan is to turn them Protestant and hopefully absorb into the HRE.
I mentioned Spain earlier. Spain is now my ally, replacing Venice. It's been a surprisingly good relationship. They're the Defender of the Faith, but by this point in the game I don't need to declare on many Catholics, so so far it hasn't been a problem. Geographically it seems to be working out all right, with the Mamluks willing to aid me against Muscovy and Ottomans, and Spain willing to aid me against western Europe. So far it's mostly been a defensive relationship though: I like having their numbers on my side to discourage coalitions from declaring, but haven't felt the need to call them in to any offensive wars yet. The Venetian/France war was a pretty fun and interesting cooperation though, as we were technically fighting separate wars and not allies but in practice attacking the same people at the same time.
Burgundy and Holland have been really quiet since the Lowland Revolt. The most interesting development here has probably been, well, development. In another first for this time, I'm now directly collecting from trade in multiple nodes instead of trying to steer everything. I automatically collect in Saxony, where I have a bit over 50% Trade Power; due to caravan power, it's really hard to get more than that. I also have merchants collecting in the English Channel, the Baltic Sea and, hm, I think Krakow. The English Channel is the most profitable of those, despite me having a relatively small share and England dominating. Anyways, I've been developing those lands, building marketplaces, upgrading Centers of Trade, accepting cultures and generally making it into a cash cow.
Er - on cultures, I guess it hasn't been universal. I did accept Dutch and Flemish early on to try and keep the Lowlands under control. The Walloons were a smaller minority, so I've been culture-converting them to Flemish for a while now. Which, again, seems historically accurate, especially in how mad it makes people! After I switched primary culture to Saxon and became an Empire, I was surprised to see that Dutch and Flemish were automatically accepted as part of the Germanic culture group; for some reason I'd assumed they were separate. So that freed up two valuable Promoted Culture slots; I promptly promoted Burgundian, who have a relatively small portion of provinces but a relatively large share of development. I think I've pretty much completely eliminated the Walloons from my border.
Anyways, this may be a long-shot but I'm curious if I'll be able to force Global Trade to spawn in my empire. Right now the English Channel is the second-wealthiest Trading Node in the world, behind Venice but within shooting distance of it. England has roughly a 2/3 share to my roughly 1/4 share, BUT I experimented for one month with making all my merchants steer towards the Channel instead of collecting, and that pushes me up to about 40%. My harebrained scheme now is to take London: not so much for its wealth or its Great Project, but just for its Provincial Trade Power, which I think could tilt the scales in my direction. I've fabricated claims on Sussex and Kent, and will decide in the next decade or two whether to take the plunge. Which, again, is a good reason for my navy. I'm ahead of England in tech, so this could be a good time to strike. Oh, and similar to taking Novograd, I'm 99% sure that taking London will keep England from being able to form Great Britain, which again will help me avoid a more dangerous foe in future centuries.
I'll write more about Protestantism later, but real quick on the Reformed movement - I successfully squashed the first two Reformed Centers of Reformation in Europe, which has been awesome, as only a handful of countries converted. It took me a while to realize that the third one had spawned in the north of Scotland, which is too far away for me to do anything about, but also it's actually been pretty great to have it up there. It's almost exclusively been converting in the UK. Scotland flipped to Reformed, which made tensions with England stronger, which mitigates the risk of Great Britain forming soon. Britain has remained Catholic again like they did in my last game, rejecting Anglicanism; but a good chunk of their provinces and most of Ireland have since become Reformed. I can only imagine that this is creating significant unrest in the country, which makes me smile.
I don't think I chatted about Institutions yet. I was lucky enough to get Printing Press to spawn in my lands, very near the Austrian border. I did everything I could to encourage its spread, including taking Church Powers, trying to stay at peace, and using the Edict everywhere to encourage it. Still, I ended up being one of the last countries to Embrace it. It takes a lot longer for large countries to get enough Institution spread to take it, while small nations can immediately switch for free as soon as a single province gets it. My memory is slightly fuzzy, but I think I wasn't overly concerned about the next sets of techs unlocking, so even once I could afford embracing it I let it continue spreading naturally for another year or two, finally unlocking a few days before an Innovative technology bonus was about to expire. This ended up saving a ton of ducats and monarch points.
Continuing north: I've had pretty great relations with Denmark and Sweden for much of the game. All three Protestant Centers of Reformation were pretty close to Scandinavia, and they got a decent number of provinces converted early on; then one day I looked, and they were totally Protestant. I suspect that this is connected to a Mission or Decision or something, as it seemed way faster than normal.
For quite a while I was toying with the idea of allying Denmark and/or Sweden, as they like me a lot and can influence my north in the same way Spain influences my west and the Mamluks my south and east. I haven't pulled the trigger on that yet, though, mostly because their armies seem so puny that it doesn't seem worth it.
Okay, let's plunge ahead into the Holy Roman Empire!
My goal all along has been to be the Emperor of a Protestant Empire. For the first century-plus of the game I was effectively a saboteur within the Empire: an Elector who voted for weak Emperors, and a Hussite who fought internal wars and forced religion on other Princes. Austria was deposed as Emperor after two early humiliating wars against me, and never rose again as a Great Power. The emperorship rotated through a series of other weak princes. I think Austria had managed to pass the first Reform, but a subsequent Emperor was forced to revoke it, and Authority stayed low.
Once the Reformation started, I flipped Protestant, as did nearly all the other Hussites, and I aggressively focused on converting still more princes to Protestantism. With the head start of Hus, the Leagues were dominated by Protestants by 1553 or so. Austria had finally regained the Emperorship, while I think 6 of 7 electors and maybe 2/3 of the princes were Protestant. As Austria was no longer a Great Power, all of their alliances and rivalries were within the Empire itself. Unlike in my Portugal game, no external great powers had declared yet for either league. The only even medium-sized nations to declare were Denmark and Sweden, both on the Protestant side.
I obviously planned to join the Protestants, but wanted to be strategic in doing so. By this point I was the #1 Great Power and was rivaled by Muscovy, Ottomans, France and England. If I declared for Protestant they were almost guaranteed to join the Catholic League. I had to wrap up another war first, though, and was nervous about the League War firing too early: the Protestant side dwarfed the Catholic side, and the current Protestant leader (I forget who, but maybe Friesland?) was probably tempted to get the party going ASAP.
I eventually did something I've never done before: broke a truce. Once my previous war wrapped up I joined the Protestant League and became the League Leader. I still had a couple of years left on my 15-year truce with Austria after our last war, but I went ahead and started the Religious Superiority war with them anyways. Thanks to having completed the Diplomatic Ideas, this was merely a -3 Stability hit rather than the typical -5.
I wrote a long post earlier about World War Zero during my Portugal game. This time around I started calling it World War Negative One: it was to WW0 as WW1 was to WW2. WW0 was a truly global conflict, with battles raging all throughout Europe, Africa, the Middle East, South American colonies invading North American ones, epic naval battles off the coast of Sumatra, island-hopping marine invasions throughout the Pacific, and more. By contrast, WW-1 was exclusively a European struggle, and mostly focused in central Europe, with the larger nations watching from the periphery.
The timing was pretty different as well. WW0 had started right around 1600 and delayed my embrace of Absolutism; WW-1 kicked off around 1553 or so. As another nice benefit, that meant the Counter-Reformation was much shorter in this game. I think the Reformation fired shortly after 1500, the Counter-Reformation began around 1540 and ended around 1553, so the Catholic countries had a very short time; being outside the church I couldn't check the status of the Council of Trent but even if they had unlocked everything they only had a couple of years with those modifiers.
Militarily, it was a much easier fight than WW0, but still my favorite war to date in this game, with significantly more participants than usual. The AI is actually pretty good, managing to sneak around to some underdefended areas, and less suicidally attached to ongoing sieges than they were in earlier versions. I could have enforced religion relatively early, but looked at the whole war as a great opportunity to reshape the HRE in my own image, so I separate-peace'd all the Catholic members of the league (as opposed to all the Catholic League members), force-converting them to Protestantism before letting them go. Austria stood alone in the end before I finally enforced my will. I took a few more provinces from them too, getting a few steps closer towards my centuries-long goal of creating a land bridge between Burgundy and Bohemia. This made my Aggressive Expansion soar to previously unseen heights; I'm curious if trucebreaking to start a war increases the AE of any provinces you take in the end.
Most of my focus since then has been on whipping the HRE into shape and speedrunning Reforms. I had to put in a bit of work early to ensure my continued leadership of the Empire: I had annexed Saxony and Brandenburg during the war, so I had a big malus from that on top of maluses from AE; but as the new Emperor I got to appoint the new Electors, so I chose two new Protestant nations that I had released from Catholic League losers. I think the new ones are Lippe and Nassau. They come with a huge relations boost from liberating them, so despite not being vassals they actually supported me more than Saxony or Brandenburg had. The other four Electors hated me, but fortunately they couldn't agree on who they preferred to replace me, and as the Emperor only requires a plurality of votes I was set.
We emerged with the League War with a strongly positive Imperial Authority monthly amount, further aided by the Historical Center of Prague and my Bohemian Ideas. I was still getting some small maluses from heretical princes and for four Imperial territories held outside the Empire. When I got opportunities, I would start a war to enforce religion; often this meant attacking some third party and pulling in the heretics. It isn't necessary to co-belligerant them since you aren't taking provinces and there are no extra penalties on Force Religion for non-belligerants.
After finally (re-) passing the first Reform, I unlocked the Imperial Ban. My first target was Denmark. I didn't have any particular animosity towards them, as they had helped in the war and weren't actively threatening us, but I still wanted those provinces. I think this was the first time I actually made use of my own navy in a war, having invested in a few Heavy Ships along with my existing English Channel trade fleet. This one wasn't a total war, and I think we peaced out right around the time we took the capital; I mostly just wanted those specific provinces. I was able to return one to its original owner, and only had a small amount of AE for directly taking the other.
Oh, man! I haven't talked yet about the Protestant religious mechanics. Here we go:
The more I play EU4, the more impressed I get at how not just dense but also varied it is. Religion is a great example. My assumption would be that, similar to Civilization, religions offer different flavors and maybe alternate bonuses, but are all the same system. That's not at all the case in EU4, though. Catholicism has its own system with completely unique user interfaces, mechanics, and strategies than Protestantism, which in turn is very different from Orthodox, Coptic, Sunni, Shiite, Buddhist, and so on.
I'd gotten to know Catholicism very well during my Portugal run. The gameplay there is oriented around the Holy See. The Papal States are the in-game manifestation of the Church, and like other countries they own territory, command armies, have diplomatic relations and so on. But there is also a "Curia Controller", which is the country that "controls" the Pope; sometimes this is the Papal States but often it's a major Catholic nation like France. The Curia Controller can make major decisions that affect all Catholics throughout the world, like excommunicating disliked monarchs, calling for a crusade against infidels, issuing Golden Bulls that give a specific bonus to all Catholic nations, appointing new bishops, conducting the Council of Trent and so on.
The vast majority of Catholic nations will never become the Papal Controller and need to abide by the Pope's decisions. But they do gain "Papal Authority". You can get small amounts through various means, like events, having a loyal Clergy estate, buying an Indulgence, and so on. But you can also get a lot of Papal Authority by converting heretics and heathens to Catholicism; as Portugal, I had an entire world of natives to convert, both in my own direct territory and those of my colonial nations. You can then spend Papal Authority to unlock powerful bonuses, like increased diplomatic efficiency, higher morale for your troops, or a one-time boost to Mercantilism. You can also use your Papal Authority to lobby to become the Papal Controller for the next Pope, but this tends to be a very inefficient usage; everyone else is competing and you're much better off spending on known results than taking a gamble.
Thematically, then, Catholicism is very pyramidal and hierarchical in gameplay as well as in lore. At the very top are the Papal States and the Pope, who receive a flow of money throughout the whole game pouring into the Curia coffers. Then there are the large and wealthy major Catholic nations, who have the geographical and financial resources to get the most Papal Authority and earn the most benefits while influencing the course of Catholicism. And the vast majority of Catholic states are the small, poor and powerless ones who just passively accept whatever Golden Bulls are handed down from on high but don't have any way to influence the Church.
Protestantism is completely different. There is no global Protestant organization and no inter-national bodies; the decisions I make as the Protestant church in Bohemia have zero impact on Protestant churches in other nations. You do get the standard "Same faith" relationship bonus with other sect followers but that's it.
Internally, Protestantism is much flatter (more egalitarian) than Catholicism. Each nation gains "Church Power" over time. Once you reach 100 points, you can select a Church Aspect, which gives an ongoing bonus to your nation: you can pick something like steady increases to Legitimacy, or Army Morale, or lowering National Unrest. You can have up to three Church Aspects available at a time, and can cancel one and replace it with another once you have sufficient Church Power.
Mechanically, this gives you the flexibility to shift your Aspects, such as focusing on military ones during times of war and economic ones during times of peace. Thematically, each state is in charge of its own destiny, with no central authority dictating how to worship or how to behave.
Annnnyways, back to the HRE! I'd long since become the Protestant Defender of Faith and have well over 50 Protestant nations in the fold. Surprisingly, nations don't get very mad at me attacking them and forcibly converting them, those maluses typically burn off in a couple of years while the Aggressive Expansion from taking only a few provinces can last for decades.
In a couple of cases I had to beat up the same people twice. Inglostadt was probably the third-largest HRE member after myself and Austria. I forcibly converted them to Protestantism, but only a decade or so later they flipped back to Catholic. That's annoying but understandable: only the capital province actually changes religion when the nation undergoes a Force Religion change, so if it's a large nation and all the other provinces are Catholic, then they'll probably choose to switch back once they can. This time around, I decided to follow my tried-and-true approach of hitting big guys to turn them into multiple little guys; specifically, I released Landshut, which automatically came out Protestant. I forced Inglostadt back to Protestant; I'd seen through the Religious map mode that their two remaining Catholic provinces were already being converted by Protestant Centers of Reformation, so I think there's basically zero risk of them returning to their old faith again.
I had a similar fight against Switzerland, this time taking some provinces for my under-construction land bridge: I don't think they had similar releasable nations, or if they did, they would have come out Catholic and not really helped me with my whole Heretic Princes problem.
The last big war I had was against Venice. I wrote about that up above! Venice isn't in the HRE, but some of its allies were, and once I forcibly converted Sienna and Geneva I was down to just two Heretic Princes left. Austria is one, which I want to leave alone for a while: I'm definitely going to fight them again, and would love for them to be unpopular outcasts when I do so. The other is Frankfurt, a lone Reformed Free City. I check its alliances web every few years and it always ends up looking like way too big of a pain. A mere 2 heretic princes (not electors) out of 58 nations in the HRE isn't bad at all! Now that I have all our Imperial Territory back, I'm earning Imperial Authority at a whopping 0.50 IA per month, which is awesome. I've already taken the second Reform and am more than halfway to the third.
What I'm really looking forward to is unlocking the "Expand Empire" casus belli. Once I have that, I plan to start declaring on the Black Sea Christian nations to try and expand the HRE out there. Most of central Europe is already in the fold, but there are a few stragglers like Ragusa I'd like to take in, and longer-term I may try to re-establish the Empire in Italy. (Though I also may want to take some, most or all of those provinces for myself, I still need to figure that out.)
Playing in the HRE continues to be great fun. I very much feel the Machiavellian "it is better to be feared than to be loved" thing. Most HRE nations have a negative opinion of me due to my Aggressive Expansion, which I can somewhat offset via Improve Relations; and yet, the Electors are currently unanimously supporting me, just because I'm so powerful. Whenever I have Overextension the Princes oppose my reforms, but as soon as I finish coring they're willing to support me. It's a fine tightrope to walk, and fun to balance.