:confused:

I didn't play a game of civ in a while, so I decided to play and use all the warlords and BTS goodies. So I got myself 2 vassals by capitulation (never chose that before) and they are on my continent. No one else is there.

Now I'm planning to invade the the other continent with 6 AI. So I conquered a medium sized island just of the coast of that continent and took Justinian, which was created as a colony by Caesar. Once I took it and destroyed Justinian I made peace with Caesar (Justinians master). I then created a colony from that island I just conquered, and to my surprise my two vassals (Mao and Tokugawa) immeadeatly break free.

Now why is that, or is this a bug?

I don't have BTS, it might be a bug. However, did you consider the drop in population from creating a colony? As your vassals grow, you have to grow too or they break free. IIRC, colonies only count 50% toward your land/pop, and if that makes you smaller than them, they could break free.

Still, that doesn't seem too likely an explanation to me, since you lost BOTH vassals instantly. Maybe someone else can help him on this?

It never happened to me, so I don't know how this exactly works, but AFAIK if one of these three conditions is violated your vassals may break free:
- more than 50% land than the master
- more than 50% population than the master
- less than 50% of the land area at the time of capitulation

Since you conquered Justinian after you subdued Mao and Toku I guess the population requirement may be violated, since the land can hardly be the factor.

The pop-count is worth checking, allthough it would be strange that both vassals at the same time reach this limit.

Land-wise, it didn't change much after when they became vassals, the complete continent was already occupied so no big changes have occured.

I'll load the pre-turn auto save, just to check the pop count.

Ok, checked it, and this couldn't be it.

The numbers:
__________________Mao _____ Toku ____ Limit to break free%
land of master______26%_____ 27% _____ max=50%
% Pop of master____25%_____ 11% _____ max = 50%
% land original______111% ___ 114% ____ min = 50%

The land I made a colony was all new land, ie I took it after Mao and Toku became vassals.

Sounds like a bug then. Do you use Bhruic's inofficial patch for BtS 3.13? It fixes several bugs, perhaps yours too.
Bhruic's patch (http://forums.civfanatics.com/showthread.php?t=246057)