Gain land by pressing claims of others?

Question

This seems to be a question for myth busters. The point is that the claimant that I press will become my vassal. Everywhere I search for an answer people are answering differently.

• The claimant should not gain a higher title then yours.

To me this means I can vassal an entire kingdom if I am emperor or a county if I'm a duke by just inviting someone with a claim to my court and press his claim in a war. He will become my vassal and my land spreads

• You should land the claimant a higher title then he can gain

In this case you can only do this as a king (or perhaps petty king?) since as a duke I have to give away my title of duke in order to gain a county as a vassal. Likewise, this seems unwanted if I'm an emperor, as the emperor of 3 kingdoms I would not want to give away 1 kingdom in order to gain a duchy.

Even if I could gain a kingdom I would end up with a vassal holding as much kingdoms as I do making him extremely powerful.

Answer 1

There are a few factors here.

First, the claimant must be able to become your vassal after the war. This means the title being claimed must a lower level than your own.

For example, if you are King of France, pressing someone's claim to the Kingdom of England means they cannot be your vassal. If you land them first, they'll just become independent and you'll lose the old land.

Second, one of the following must be true:

• If the new land is par of your de jure realm, the new holder becomes your vassal automatically.
• If the claimant is part of your dynasty, they will become your vassal. Marry dynasty members to characters with inheritable claims so their children will be claimants of your dynasty.
• Landed vassals will remain your vassals if possible. It doesn't matter what land they have- even a single barony is enough. This is the easiest method but involves giving away personal holdings.