If you've played Crusader Kings II for any decent length of time, you've almost certainly encountered what happens when vassals get too strong and dislike you.
If any single vassal gets strong enough to challenge your power, you're at constant risk of rebellion. Everything you've worked for could be undone in years. Thus I'll be going into how to prevent this from happening, concentrating on keeping your vassals weak.
The Basic Concept
To prevent sizable rebellions, you have one primary goal: Prevent your vassals from having more power than you. This is achieved in multiple ways.
First, you have to keep yourself strong.
Second, you don't want your vassals to hold a lot of titles.
Third, you don't want your vassals to have a lot of vassals.
Fourth, you want to keep your vassals happy.
Keeping Yourself Strong
Keeping yourself strong in the long term primarily relies on two factors: Number and concentration of holdings, and construction.
You want to hold every single county in two duchies you own that are either bordering each other, or very close to each other. These two duchies should together have 7 to 10 counties so that you can use most of your demesne limit without having to construct holdings.
By keeping your entire demesne in two duchies you avoid the penalty from having more than two duchies, and you avoid the penalties for vassals desiring your duchies. No vassals will thus be able to plot for your duchies, thus keeping your powerbase secure.
The advantage of keeping your demesne limited to a small geographical area is that you can now gather up your army very quickly, so you'll be able to respond quickly to any rebellion with very low risk of your units being picked off separately.
Second, you want to upgrade your holdings as much as possible. This is covered in further detail in the installment on construction.
By upgrading your holdings you'll have more money available, and more troops. You'll also refill your levies faster, so you'll be able to recover from wars faster.
As your vassals will seldom be able to upgrade their holdings to the same extent as you, construction can give you a large advantage.
Keeping Your Vassals Weak
The other side of the coin is keeping your vassals weak, and reducing their powerbase when possible. If you expand via conquest, you'll often have titles that you need to give out. You should be quite careful about who you give these titles to, as it is easy to end up with a single vassal holding many titles, and eventually being able to challenge your power.
The strategy I recommend for giving out counties goes like this: Search for characters that are not rulers, are of your religion, are male, and are of your culture. You should then sort by dynasty, and scroll down to your own. You should now find someone who is not heir to anything, and whose heir does not own anything. You then give that person a single county with all its holdings (if applicable). The new count will then soon make the holdings in the county into vassals, and will be of no threat to you.
For duchies you do much the same. Search for characters that are rulers, are of your religion, and are of your culture. Sort by dynasty, and scroll down to your own. Find someone who owns a single county or barony. One county and one barony is also fine, but only a single holding is preferable. This person should get the duchy. It does not matter if (s)he actually holds any counties within the duchy; that is their problem, not yours. By following this strategy you'll end up with dukes who hold a single duchy and a single county, and will be unlikely to ever be able to challenge your power.
Whenever a vassal rebels and you beat him, you should strip him of his primary title. To do this you will need Limited Crown Authority. You can then follow the strategy described above to give this title to someone else.
Further, you can deliberately make strong vassals rebel so that you can imprison them and strip them of a title. Simply give them the court jester honorary title, and raise their vassal levies and just leave them there. Eventually they will rebel, and then you can crush them and take a title from them.
Another way to make them rebel without incurring tyranny is imprisoning them with a just cause. They'll rebel approximately half the time, and upon crushing their rebellion you'll be able to strip them of a title. If they don't rebel you can just ransom them, thus taking a bit of money from them and giving it to you, and you'll likely end up with another reason to imprison them later.
Beyond how you distribute county/duchy grants, and stripping of titles, it is very important to attain Medium Crown Authority.
Medium Crown Authority will prevent all intra-realm warfare with the exception of rebellion. This will make it near impossible for your vassals to expand via conquest, and they're thus much more likely to remain weak. They'll also not be using up huge amounts of levies on pointless internal wars, so you'll have the levies you need when you go to war.
Keeping Your Vassals Happy
Finally, you should do your best to keep your vassals happy. The two most important ways of doing this is keeping your vassals the same culture as you, and keeping them the same religion as you. This lets you avoid the large 'foreigner' penalties, and you get -15% risk of rebellion for each. Having all your vassals of the same religion is especially simple, as at Medium Crown Authority you can revoke any title held by a Heretic or Infidel without incurring tyranny.
For culture you should simply make sure to never give titles to people of a different culture unless you have a very good reason to, for example so as to push their claim on some other title. You can also like described above, deliberately make them rebel so that you can give their titles to someone else.
Further, you should groom your heir yourself. Unless you have good reason not to, your heir should always be your ward, not someone else's. This will let you make various choices throughout his childhood, thus having him end up with good traits. A few good traits can make a huge difference both when it comes to chance of rebellion, and the levies and taxes he can get from his vassals.
Finally, apply bribes and honorary titles strategically. Unless you actually want someone to rebel it is usually better to pay them off with a bribe than to have to crush their rebellion. Do note that honorary titles only expire upon the recipient's death (or rebellion); they'll even persist beyond the ruler's death. As such you should be careful about when you give them out, as there's a rather limited number of them.
Summary
Keep your vassals happy and weak, and yourself strong, and it becomes much easier to hold onto the throne.
My tips are as follows:
- When giving out a county, give it to a dynasty member who holds no other titles
- When giving out a duchy, give it to a dynasty member who holds a single county or barony
- After crushing a rebellion, strip every member of the rebellion of their primary title. You'll need Limited Crown Authority
- Revoke the titles of any infidels and heretics. You'll need Medium Crown Authority
- If any vassal is getting too strong, induce rebellion then strip him of a title
- Avoid having vassals of different cultures and religions. Inducing rebellion can help
- Get Medium Crown Authority, it will stop vassals from expanding via intra-realm conquest
- Hold every county in two bordering duchies
- Upgrade your holdings as much as possible
- Be your heir's guardian
- Give out bribes and honorary titles to prevent rebellion
Written by Meneth