I started my first Rome2 game as the Breton faction. I subdued Britannia except for one region, which is my defensive ally.
When I go to the diplomatic menu, I have the "confederation" option, which seems to be simple assimilation. But no option for State client or satrapi.
Does the ability to creat cleint states depend on your culture? Is confederation the only option for Celtics to subdue pacifically ?