I'm a province of the Roman Hegemony and I appear to have hit my expansion limit, as all my borders are friendly, and I'm a vassal so I can't even declare war if I want. I don't have anything to do other than send my armies to assist the Roman Hegemony against the Huns. I'm not really sure what the next step is. In all the other campaigns I merely conquer the world and declare war against everybody, but as a province/vassal, I feel very limited. Am I supposed to rebel against my master?