Although it might not seem like it when you start as a Catholic ruler, there are a lot of Casus Bellis (CBs) in Crusader Kings 2. Far too many for me to go through them and explain what they all do. If that’s the information you’re looking for, take a look at the Casus Belli section of the CK2 Wiki. What I’m going to be focusing on instead is how you actually go about earning these CBs. Understanding the theory and practice behind earning a CB will ensure that you never have to be at peace for long.
For complete religion and church guide, see here: Religion & Keeping the Church Strong. Popes The pope has several powers. The first, and strongest, is crusades. The pope can call a crusade as long as the moral authority of the catholic church is 5% or higher. This calls for a religious war, generally against muslims, but after 1198 crusades can also be called upon pagans.
Fabricated Claims
- You need a title that is the liege/overlord of the title you fought for them. I.e you got a person a county, but you need a duchy title that has the county inside to be able to vassalize them. Boards Crusader Kings II.
- Code Something like that should work, it's off the top of my head but it -should- work. This way you can scope directly to the desired spouse via the eventtarget:secondaryspouse1/2 so long as the event chain is unbroken (might need to make it a global event target if the chain is broken, in which case you'd want to limit who can get the events to avoid crossing targets, like making it.
- Its really not that much to deal with. You click a button to turn one of your bishops into an antipope. He gets an immediate strong claim on the papacy. You declare a war that you can pretty much instantly win because the pope has no allies and barely any levies. Your antipope becomes the official pope and stays your vassal as long as you're an.
In my original guide, How to Get Married and Go to War I briefly touched on the ability to fabricate claims on your neighbours. Simply tell your Chancellor to sit in a neighbouring province and he’ll have a percentage chance over time to generate you a claim. The chances of success are based on your Chancellor’s diplomacy stat, and with a high enough stat he can even create a claim on a whole duchy if the target holds one.
Although this is powerful when it works, the low chance of success and the fact that it’s entirely up to chance makes this a very unreliable method of expanding. It’s often worth using your Chancellor for this, but not as your exclusive method of expansion.
Press All Claims: Another strength of fabricated claims is the ability to press multiple of them in one war. If you have multiple claims on a target, you earn the new CB “Press All Claims” which, if you are successful, will give you all of your claims on the target, rather than just one county. Even better, as long as you start the war with this specific CB, any claims you fabricate during the war will be added to the victory condition of “all claims”. If you can afford to wait for multiple claims to generate, this is a great way of expanding quickly as a small count or duke.
De Jure Claims
De jure is Latin for “from law”, and is Crusader Kings’ way of dividing the map into various duchies, kingdoms and empires. Every province belongs, de jure, to a duchy, every duchy to a kingdom and every kingdom to an empire. This system governs multiple different mechanics, but the most important for this guide is the de jure claims.
When you are the holder or liege of a ducal title, you can ‘legally’ expect to be ruler of all of its constituent counties as well. This grants you the special “de jure claims” Casus Belli, which allows you to declare war to take a single county belonging to a duchy under your rule. You can only declare for one at a time, which makes it somewhat slow, but is a great way for dukes to consolidate their rule.
To generate a de jure claim you need to be a duke, which means creating a duchy title. To create a duchy title, you need to hold more than 50% of the counties that are part of that duchy (or otherwise generate and press a claim on the duchy title itself). So, in order to get access to this CB, you need to already have enough land to create a duchy, making it not so great for expanding as it is for consolidating power. However, if you can get your hands on a duchy, it is often the most convenient way to increase your realm size, and each duchy will have its own de jure claims for you to press.
Inherited Claims
Inheriting claims means playing the long game, but when you have 400-700 years of game play, it’s just a drop in the ocean. When a ruler dies, they pass claims onto their children, no matter what their succession law actually is, as well as passing claims onto the second and third in line of succession. Those in the line of succession will gain strong claims, and everyone else will gain “weak claims”.
The important thing here, is that these claims can also be passed on to the children of the character who has them. So, if you want a claim on someone’s land, then marrying their daughter is a good way to get it. Their daughter will gain a claim on that land when her parent dies, then her children will gain claims when she dies. If her child is your heir, you’ll eventually have that claim for yourself.
This isn’t a great way to grow right now most of the time, so don’t use it for your short term goals. But, it will help you to secure claims further down the line, and with intelligent marriages you can end up with a lot of potential claims somewhere down the road, so that you’ll have plenty of options. Intelligent marriage is something I’ll be covering in another guide, but marrying for claims is one of the most important aspects to look out for in a spouse.
Weak Claims: Weak claims are a special form of claim that you can’t always use. A weak claim is the game’s way of representing that you have some legitimacy in claiming the title, but not over a strong ruler who already has it. As such, you can only press weak claims on characters who are currently in a regency (which usually means being incredibly ill, imprisoned, or a child), a civil war, or who are female. In order to press these claims you’ll need to either be patient, waiting for the right circumstances to come about, or engineer a situation yourself.
Claimants
Of course, you’re not the only one with claims on other people’s titles, and inviting claimants to your court is a great way to grow your realm, as long as you don’t mind sharing. When you press someone else’s claim on a title, their land will become part of your realm if:
- They are already your vassal;
- They are of your dynasty; or
- The land is de jure part of your realm.
Using oft in outlook 2013 for mac. Of course, they also have to be a lower rank than you. A duke can’t have another duke as their vassal, for instance.
Finding people with claims and inviting them to your court is strong, but hidden away in the complex interface. First, find the title you want a claim on by clicking on its shield in the character view. Once you’re at the title screen, there will be a button for “Claimants”. Click this and you’ll have a list of people with claims on the title, as well as thumbs up or down based on whether they’ll come to your court. If no-one will come, try to bribe one of them for a favour, and invite them that way.
Once you’ve invited a likely candidate to your realm, the easiest way to absorb their claim into your realm is to make them a vassal before declaring the war. Give them a landed title, then go ahead and press their claim. Once you win the war, they’ll take over the land as your vassal, bringing it into your realm.
Sanctioned Invasions
If you dream of grander prizes than a simple county or duchy, then you can always ask the Pope to sanction your invasion. This CB is relatively easy to find, but difficult to pull off for multiple reasons.
To request an invasion on another character, you need to have the same religious head (which in Catholic terms means you can only use it on other Catholics). You also need to have a claim on the target’s realm, or have a smaller realm size than them. As a method of generating a CB, we’re mostly looking at the latter. Being smaller than the target often means being weaker, which is one of the reasons that this is difficult to pull off, but often generating the CB is the harder part.
In order for the Pope to grant you the powerful Invasion Casus Belli, he must like you more than the target in question. He also has to dislike the target, who also must have less cardinals than you in the college of cardinals. All of this is difficult enough, but to say that you can only request it against someone larger than you narrows your options even more.
The best way to go about this is to get the Pope to adore you, by sending your Court Chaplain to improve religious relations in Rome. You can send your Chancellor there as well if you want to double down on it. Check on neighbouring kingdoms to see who the Pope dislikes, and keep an eye on them. Be patient, and you may get your chance.
It’s rare that you’ll get the opportunity to use this CB, but it’s always worth knowing about. If you can get it, it allows you to take the entirety of a neighbouring kingdom in one war, vastly improving your own standing and removing a threat to your own rule.
Holy Wars & Crusades
Create Antipope Ck2
The Holy War Casus Belli is enable when you border a ruler of a different religion. This CB can be used for any neighbouring duchy that borders your land, and on success will grant you every title in that duchy that the opposing ruler and his vassals hold. Any vassals of your religion will become your vassal, rather than giving up their land. This is a great way to expand quickly, gaining up to 6 provinces at a time, but comes with its own downsides. When you declare a Holy War, any ruler of the same religion as the defender can join in if they border either you or the defender. Basically, everyone nearby is going to get involved, so don’t declare if an alliance of multiple neighbouring states could beat you, or declare intelligently when everyone nearby is distracted.
Ck2 How To Vassalize Pope
Crusades are a special sort of holy war, called by the Pope. The Pope will declare a Crusade for an entire kingdom title against a non-Catholic ruler who holds lands in that kingdom. Any Catholic ruler can join a crusade, and any ruler who shares a religion with the defender can join to defend them. It gets pretty messy. If the attackers are victorious in a Crusade, then all the land in the kingdom title will go to the ruler who holds the crown, if any. If there isn’t one (a crusade for Jerusalem, for instance) then the entire kingdom will go to the ruler who ‘contributed’ the most, which in this case usually means lost the most soldiers. The more soldiers you send and the larger battles you participate in, the higher your chance of gaining a kingdom title out of a crusade. There’s very little control over who a crusade is called against, however, so it’s not worth trying to engineer. Simply understand when you might be able to gain some land out of it.
An Exception: The one exception to the ‘differing religions’ activation of Holy Wars and Crusades are Orthodox and Catholic Christians. Orthodox and Catholic rulers don’t gain the Holy War CB on each other, nor can Catholics crusade against Orthodox rulers (Orthodox Christianity has no Crusades whatsoever). However, they also don’t count as being the same religion for defensive calls, so operate on a strange, uneasy balance when bordering each other.
This is just part 1 of the Casus Belli series, and focuses on the CBs that will generate more land for Catholic feudal rulers. In part 2 I will shed some light on non-territorial CBs, and why you would use them, as well as some CBs that are available to non-Catholic, non-feudal rulers.
Ck2 Vassal Pope Crusade
As ever, if you have any thoughts or questions, please do drop a comment below for me.