in ancient Rome, a board of three officials. There were several types: Tresviri capitales, or tresviri nocturni, first instituted about 289 BC, assisted higher magistrates in their judicial functions, especially those relating to crime and the civil status of citizens. Tresviri epulones, originally a board of three priests, was created in 196 BC to take charge of the banquet of Jupiter, the key event in the festivals of the Ludi Romani and Ludi Plebeii. Tresviri monetales were in charge of the mint for Rome and Italy during both the republic and the empire. Tresviri rei publicae constituendae (“triumvirate for organizing the state”) was the title granted in 43 BC for five years (renewed in 37 for another five) to the group generally known as the Second Triumvirate (Mark Antony, Marcus Aemilius Lepidus, and Octavian 【the future Emperor Augustus】). Under it they received absolute authority, dictatorial in scope. The so-called First Triumvirate of Pompey, Julius Caesar, and Marcus Licinius Crassus, which began in 60 BC, was not a formally created commission but an extralegal compact among three strong political leaders.

Boards of three persons, usually elected, called triumviri agris dandis assignandis (sometimes also judicandis) and triumviri coloniae deducendae were frequently placed, respectively, in charge of assignments of land and in charge of the founding of colonies during the last three centuries of the republic (3rd–1st century BC).