Tribunes were a position held by officers within the Romulan Star Empire.
Overview
The Romulan's that held this title were members of the High Tribunal. They were delegates from certain fleets that were elected though in some cases they were the most senior flag officer who served as their representatives. A Tribune remained at their post on the High Tribunal for several years after which the honor transfered to a new representative.
Among the Tullan and Praetorian Fleets, the position was given to the most honored officer whilst in the core fleets, they were selected by their patron Senator or coalition.
Tribunes were known to ally with one another on matters relating to fleet deployments, allocations or simply to undermine rivals. (LUG module: The Way of D'era: The Romulans)