The Romulan Senate was the governing body of the Romulan Star Empire and headed by the Praetor (Rihannsu: Fvillha).
Senatorial elections were overseen by the Imperial Elections Commissioner. (RIS Bouteina: "Yesterday's Lyrans")
Below the Praetor were the Proconsul and the Vice-proconsul. (TNG: "Unification I", VOY: "Eye of the Needle")
Following the Hobus supernova and the destruction of Romulus the Senate was seated on Rator III. (RIS Bouteina: "Gogmagog", "Rator III Awaits")