The nature and composition of the Primogen varies from domain to domain, depending on its relationship with the Prince. In some cities, the Primogen rule directly without even a figurehead prince; in others, the council is a rubber-stamp for the rule of a particularly charismatic or authoritarian Prince. Typically the Primogen is constructed to represent all the various clans and covenants present in the city, typically in proportion to their populations, though in practice any sufficiently potent or influential elder may be able to claim a seat, while those factions currently in power are also able to stack the Primogen in their favor. 
Other names for the Primogen may include the Board, the Tribunal, the Circle or the Senate. Individual Primogen may be titled accordingly, or simply as "advisors". Primogen in Berlin are called Electors.