How to break vasalship between AI factions?

[Astarte]

Hi and good morning

I have now been playing SS again and encountered new problem; I managed to save Cuman Khanate from extinction few turns before it would had been too late, but Novgorod took em as vasals. I hoped Novgorod would just die out, since it was doing badly too, but power vacuum my armies left to nearbly lands enabled them to become eastern superpower, they are currently moving towards Bagdad. My new plan is to shove seljuks and TO against them and support them by crushing their other enemies, like Poland, but I am afraid it would not be enough and Novgorod would just annex them too, leading to situation where I have to grind thru them myself and Cumans wouldnt want to be my friends anymore.

So, to the question, is there a way how I could break their vasalship relationship? I am using that AI that doesnt break alliances (settings made years ago). I cant use jihads or crusades to pit em against each others since cumans are pagans and novgorod is orthodox.

Hjelp plz?

[Lifthrasir]

Not sure it can be done with Lusted AI
As you mentionned, alliances aren't supposed to be broken with that AI.

Have you tried to bribe Cumans (or give them donations if you prefer) to improve your diplomatic relations or to convince them to attack Novgorod to break their vassalage?

[Astarte]

I donated them new land to settle in, our relationship is fine. I tried to tell them to attack Novgorod, but there wasnt even option for that in diblomacy sheet. I think vasallage always weights more than alliance when ally and vasalmaster go to war with each other, regardless of relations? Well, to bribe them to love me just before attacking Novgorod is my last resolt if Seljuk/TO assault doesnt bring them back to their knees.

Annoying situation. All I wanted was to fill europe with pagans since christian God killed my most loved princess few hundred years ago. That would teach him to mess with me. Lithuania is now long gone and cumans are my last resolt