Triumvir or tresvir: member of a college of three members. The expression is mostly used to describe the First Triumvirate (60 BCE; Pompey the Great, Crassus, and Julius Caesar) and Second Triumvirate (43 BCE; Marc Antony, Lepidus, and Octavian).

Lepidus as triumvirA triumviratus is literally a college of three men. In the ancient Roman republic, there were several boards of tresviri. For example

The best known triumvirates, however, were less official: the First and Second Triumvirate were private agreements between Roman politicians, directed against the Senate and the People. (The Second Triumvirate was later officially recognized.)