How To Unlock Byzantium in Hearts of Iron IV

In Paradox‘s ever-present World War II grand strategy game there are a whole host of nations that canny and skilled players can form. Some are hypothetical “What If?”s which embody paths in history that never happened or came close to happening. Others like Poland-Romania or turning Italy into the Papal States are slightly off the wall. However this time we’re bringing back a fallen empire. Today I am showing you how to unlock Byzantium in Hearts Of Iron IV. And guiding you through each step, to turn a rather shaky Greece into a potential great power.

I will state here and now that this guide is focused on helping you build up and execute the method I use when doing this in my playthroughs. This is not a guide on world conquest, nor is it one about forming Byzantium to its fullest extent in the game. This guide is focused on taking you from the start of the game as Greece and then to the moment you select the decision to form it. Anything thereafter is your business. With that said let’s get to it.

Setting the Stage

As soon as the game begins you must complete the decision Place The King Under House Arrest. There are no negative consequences for doing this, as any downsides are dealt with almost as soon as you get into the next section of the tree. Soon the democratic faction will win the election. Once they do so complete the focus Bring Home the Exiled Republicans and Compromise with the Monarchists. These are essential steps and will provide you with a nice amount of Political Power. Even if your neighbours won’t be all that thrilled with you. Not that their opinion will matter for much longer.

Who needs diplomacy when you can be Byzantium?

You then need to move on and complete the Focus on Remembering the Anatolian Catastrophe. This will unlock a set of three Focuses. Of which you only need to complete one of them which is Venerate the Ancient Hellenes. The other two aren’t essential. One will boost democratic support, and the other will make Italy and Germany hate you more. Which I’d advise against for the time being. Instead, try and save up some Political Power so that before your war with Turkey you can boost the opinion of Germany and Italy so you can try and get some much-needed lend-lease from them. And possibly join the Axis if you are so inclined.

Preparing the Nation

As these focuses are completed take time to throw in a few Industrial Focuses here and there. Given how weak your Military and Civilian Economy is when you start, these will help get you as strong as possible. First do Devalue the Dracma which will lead you to a choice between Utilize Our Strengths and Force the Farmers into Factories. Utilize Our Strengths will provide you with a stronger Civilian Economy, whereas Force the Farmers into Factories will provide a stronger Military Economy. Of the two I feel that Utilize Our Strengths and the focuses leading off from it have better long-term potential. In contrast, whilst the national focus Force the Farmers into Factories has a bigger initial boost you will lack the resources to make the most of it.

You’re free to pick whichever, but I feel this is better.

With the completion of Venerate the Ancient Hellenes, you will have unlocked the next set of three Focuses. Of which only one is needed to advance to the next section. I’d go for Theban Warriors as the defence buff is decent. And truth be told it will have a bigger payoff for what you are aiming to do than the others. But you can also go for Athenian Thinkers to get an extra Research Slot. Macedonian Generals is a fine option but isn’t worth it in comparison to the others. If you want to grab a second one then by all means. But taking a third may be pushing things in terms of timing.

Developing Industry

Regardless of whichever path you wish to go down with the industrial focuses you need to make sure that you have a strong industrial base. This is to support your defensive/ambush efforts. And also so that when the time comes to advance into Turkey you can build up a large enough force to take them down and deal with Romania when the time is right. You are going to lose many guns from attrition alone. As such it may be worth holding off advancing too far with your infantry equipment just so that you can build up a good enough stockpile to fight the war. You are also going to need a cheap ship to help gain control of the seas for your Naval Invasion.

It is a standard but easy to spam Submarine.

You can either go for submarines or destroyers. But I’d go for the low-cost submarine that you get as a stock option. It is cheap, it isn’t great, but it is easy to get a few of them out. And they can provide you numbers just long enough to get the invasions off so you can then just return them to port ready for the next wave. Even if you doubled down on naval tech and buildings you simply aren’t going to get enough out in time to dominate the waters. And the manpower needed to get them out will limit your land operations. So don’t feel you need to flood them out totally.

Preparing for War

I will be blunt dear reader. The coming war is going to be brutal. Especially if you aren’t ready for it. You are going to be underpowered. And if you leave the build-up too long you could easily find yourself fighting a larger faction. Or just getting curb-stomped all the same by a Turkey that has more men and guns than you. To win the day you need to ambush and encircle the Turkish forces. And break them down into as few divisions as possible so you can launch your larger invasion. To do this you need to get as many guns, divisions, ships, and convoys as possible.

If you have the DLC the market can be a god’s send.

When you are at war you can get some Lend Lease from a handful of nations. This is easier to do in the base game/before the introduction of the International Market. I’ve struggled to get Lend Lease due to low world tension when I have done it. You can still get Lend Lease if you are in a faction if you want to join the Axis for a little while. Otherwise, you are going to have to lean heavily on the International Market. Whilst that will slow down your industrial growth, you need your troops as equipped as possible. Remove the Engineer companies from your division templates. It is better to swap the factories needed to get them into more guns and artillery.

Readying the Ambush

You are going to need at least two forces. One to hold the Turks and the other to naval invade into the territory they take from you. Arrange your forces as seen in either of the two examples seen below. Either is viable, however the second makes the invasion easier when the time comes. To help with this, build a dockyard where your larger defensive force is positioned. And try and get out as many convoys and subs as you can. You don’t need many convoys for your invasion force but they can help with lend-lease and market purchases. 

You and the Turks will have around the same number of ships when the war begins. Though ideally, you’ll have a slight advantage. You will need Naval supremacy to launch your ambush invasion. Building forts can help your forces defend but takes time. I’d personally try and get your industry up and running as best as you can. Completing the prior mentioned industrial focuses will help with this. Both this section and the earlier industrial-focused sections should be done in tandem. The order is your choice. I have seen people do this without spending any time doing industrial focuses. But the option is always yours.

The EEE Take Power

As you advance down the political tree you will get a series of events telling you that the is EEE starting to gain influence. You need to take every option that will increase fascism in your nation. The goal is to get to the point that they stage a coup and take over. Doing this is the only way that you can go down the path that leads to you being able to form Byzantium. In the meantime, you need to complete Resurrecting the Megli Idea. This will lead to an event where you can invite nations to a meeting. Selection of the option that invites all the original signatories. Given you are a fascist nation/have a government aligned with facists the event will fail either way. But if you only invite Italy you will take a stability hit.

Arguably you should still be able to do this with just Italy but it is scripted to fail so take the lesser option.

With the meeting having been a successful failure you need to move on to completing Horror and Fear. Depending on timing the coup will trigger soon after or just before this to get them in power. Completing Horror and Fear will result in you declaring war on Turkey. So you must have everything ready for the war. Ideally, you will have all of this done before the Second World War starts to kick off. Otherwise, that can complicate things. Get your forces into position if they aren’t already. And make sure your navy is ready to go. You don’t need to keep them out all the time. Just when you are getting ready to launch a naval invasion. But if you have the oil for it you are welcome to try and cap the Turkish navy the moment they launch.

The War

Once you complete Horror and Fear you will declare war on Turkey. Backed up by Romania who will Guarantee them. Whilst you will likely have fewer units overall, your goal is to encircle as many enemy divisions as possible and bring them down to as low a figure as you can. The first wave will be the strongest. Once they have reached your defensive line launch your naval invasion around the back of them. This will trap them and encircle them. Once you have wiped them out return the naval invasion force to their original position and prepare the next one. Do not launch your invasion until the enemy is at your lines.

Once they are trapped you must attack them quickly before your naval invasion gets taken out instead.

You need to make sure that you use your ships sparingly. You will have more or less a similar number of ships as the Turks will have. And with your limited industrial capacity, you will struggle to replace them. You could ask to join the Axis. I haven’t found it to make much of a difference as Germany doesn’t commit enough forces to help you. However, they may at least commit enough ships to allow you to retain naval supremacy. But you may find yourself having to fight them for territory at the peace conference. And if the war goes on for too long then the Turks and Romanians may join the Allies. Whilst this is all going on be sure to take time to continue down the political branch of your Focus Tree as far as you can.

Bleed the Enemy Dry

The goal here is to complete as many encirclements as possible. This will drastically reduce the enemy’s forces. Don’t worry about Romania. As with your larger navy, they won’t be able to invade you. And they very rarely support the Turks on land. The goal is to reduce Turkish numbers as much as possible. Ideally down to single digits. Or at least to the point that they at most have ten or so units. This can take a while. But with the right combination of national focuses and with even a modest amount of arms imports you can do this with little difficulty.

Encircle where you can. Taking their core territory can be used as bait to lure more of them into your territory.

Goodness, on my most recent attempt, all I needed was to recruit an extra five infantry divisions from my initial numbers and that was more than enough. Launching the naval invasions can require a degree of good timing. If you happen to launch it on a province that has an enemy unit on it you will struggle to take it. And be aware that if you have your defensive line too far into your territory it seems to make the enemy AI more willing to defend their coastline. Which can make this encirclement strategy almost useless.

Advance Into Anatolia

Once the enemy’s forces have been reduced to a tolerable number it is time to launch the counterattack. Depending on how you place it and how silly the AI is acting, you could just walk right into Istanbul and into Anatolia with little resistance. But crossing the straight can be difficult and costly. Opening up a second front on their western coastline can draw their attention. Take your naval invasion force and whatever men you can spare and ready an attack. Launch an invasion with the invasion force and reinforce that attack with your additional forces. From there fan out and push into their lands. And get as many encirclements as you can.

It is possible to functionally encircle any Turkish forces that are still on your side of the Bosporus by taking Istanbul via this invasion and using your remaining defensive force to flatten them. Of course, you are free to use whatever forces you may have recruited in the meantime. Honestly, that is something I tend to forget myself. But the fact I have been able to do this with more or less the starting units with only five infantry units recruited shows just how effective this strategy can be.

The Purple Phoneix Rises

Once the time the war is over complete the Focus Byzantine Themata which will unlock the decision to form Byzantium. With Byzantium formed where you go from here is your choice. Romania will remain a threat in the meantime, but a well-placed naval invasion will take them down rather easily. Depending on how long this took you, you may have enough time to take on Albania, Bulgaria and Yugoslavia before they join a faction. Doing so will unlock a decision to core them. Be warned however as taking Romania’s land will make you a target of the Soviets when they decide to take Bessarabia.

Taking Italy will put you at war with the Axis and going after the land in the Levant will put you against the Allies. Which one you choose to take on first (if any of them) is your choice. You could just stick with the land you took from the Turks and leave it at that. As the Italians will most likely try to attack you sooner or later anyway. So you aren’t going to get an everlasting peace. However, Italy isn’t the hardest target to take down. With another well-timed naval invasion, you can take them out almost as soon as they declare war on you.

And with that, this guide on how to unlock Byzantium in Hearts Of Iron IV is complete. I hope you find it useful. Whilst there may be other methods of doing this this is the most effective method that I have found. And most likely will be more efficient and effective in the hands of better players than I. So best of luck!