Personal Unions (PUs) are a critical way of expanding in Europa Universalis 4. However, it is one of the least understood game mechanics, even by players who have hundreds of hours of experience in the game.
In this guide, we will explain the basics of PUs, how to get them, and provide tips to increase your chances of obtaining one.
- Personal Unions Explained
- Royal Marriages
- Personal Union Strategy
- Personal Union Inheritance: Phases
- How to Claim Thone
Personal Unions Explained
First and foremost, both countries must be Christian nations, and they cannot be a theocracy or a republic, with the exception of Dutch Republic and noble tropics. There are several ways to obtain PUs: scripted event-based PUs, restoration of Union CB, royal marriages, or succession wars.
Royal Marriages are the most common way to obtain a PU. If a country with whom you have a royal marriage goes into disputed succession, and they die without an heir, you may claim their throne if your prestige is equal to or higher than theirs.
This will result in a succession war if there is another country with the same dynasty as you who also claims the throne.
Personal Union Strategy
Prestige is your best friend when it comes to getting PUs. Aim to have a prestige of 100 at all times. If you have the same dynasty as another country, keep an eye on their disputed succession alert. It is also essential to farm prestige as few subjects get 1% Liberty desire for each negative prestige. To keep your PU subjects loyal, farm prestige as much as you can.
If your PU subject gets someone to support their independence, you need to declare on them immediately. If you cannot get a relevant CB instantly, rival them and declare a humiliate war.
Additionally, there are some ideas that will help you with PUs, such as diplomatic idea groups, which allows you to break royal marriages without a stab hit. Influence gives less aggressive expansion and less deploy annex cause for when you need to integrate subjects.
Personal Union Inheritance: Phases
The game runs a phase system with three phases: phase zero, phase one, and phase two. Each phase has its own rule set on what happens when a monarch dies, and each country has its own individual phases.
The basic rules of when the phases begin are modified by in-game events, making it quite complex to calculate the face of a nation at a particular date.
During phase zero, there will be a dynasty spread most of the time. If there is no royal marriage but they have a dynasty of another country, it might result in a PU or succession war.
Phase one is the only phase that can result in direct inheritance, but only if the target country has 15 or fewer provinces and if you have more than double the number of provinces than them.
Phase two lasts for 20 years and is when you will see most PUs or succession wars. If the target country has no royal marriage and no dynasty, a local noble succeeds. In every other case, there is either a direct PU or, if there is a valid contestant, a succession war.
How to Claim Thone
To claim the throne, you need to have the same dynasty and higher prestige than the target nation. It gives you a claim throne CB to force the target country into a personal union for 84% war score.
To increase the likelihood of getting a personal union, you should aim to have a hundred prestige at all times, and watch the disputed succession alert in the top-left.
Personal Unions can be an excellent way to gain large amounts of territory, but they can be challenging to obtain.
Remember to farm prestige and keep an eye on the disputed succession alert to keep your PU subjects loyal. Additionally, understanding the phases is crucial to know when and how to claim a throne.