houses and princes
The rulers of the larger cities, they normally control the surrounding land as well as their cities. The normal methods for becoming a Prince are a coup(killing the previous prince), coup then get yourself elected, a coup where you kill anyone who wont support you, a coup where someone installs a puppet Prince, and a military coup. Oh and a I almost forgot, a coup.
oh and you can inherit the position sometimes, and technically the king is in charge of appointing new Princes.