TRESVIRI, or Triumviri, in Roman antiquities, a board of three, either ordinary magistrates or extraordinary commissioners.
1. Tresviri capitales, whose duty it was to assist the higher officials in their judicial functions, especially criminal, were first appointed about 289 B.C., unless they are to be identified with the tresviri nocturni (Livy ix. 46, 3), who were in existence in 304. They possessed no criminal jurisdiction or jus prensionis (right of arrest) in their own right, but acted as the representatives of others. They kept watch over prisoners
and carried out the death sentence (e.g. the Catilinarian conspirators were strangled by them in the Career Tullianurn); took accused or suspected persons into custody; and exercised general control over the city police. They went the rounds by night to maintain order, and had to be present at outbreaks of fire. Amongst other things they assisted the aediles in burning forbidden books. It is possible that they were entrusted by the praetor with the settlement of certain civil processes of a semi-criminal nature, in which private citizens acted as prosecutors (see G. Gotz in Rheinisches Museum, xxx, 162). They also had to collect the sacramenta (deposit forfeited by the losing party in a suit) and examined the plea of exemption put forward by those who refused to act as jurymen. Caesar increased their number to four, but Augustus reverted to three. In imperial times most of their functions passed into the hands of the praefectus vigilum.2. Tresviri epulones, a priestly body (open from its first institution to the plebeians), assisted at public banquets. Their number was subsequently increased to seven, and by Caesar to ten, although they continued to be called septemviri, a name which was still in use at the end of the 4th century A.D. They were first created in 196 B.C. to superintend the epulum Jovis on the Capitol, but their services were also requisitioned on the occasion of triumphs, imperial birthdays, the dedication of temples, games given by private individuals, and so forth, when entertainments were provided for the people, while the senate dined on the Capitol.
3. Tresviri monetales were superintendents of the mint. Up to the Social War they were nominated from time to time, but afterwards became permanent officials. Their number was increased by Caesar to four, but again reduced by Augustus. As they acted for the senate they only coined copper money under the empire, the gold and silver coinage being under the exclusive control of the emperor. The official title was “tresviri aere argento auro fiando feriundo.”
4. Tresviri reipublicae constituendae was the title bestowed upon Octavianus, Lepidus and Antony for five years by the lex Titia, 43 B.C. The coalition of Julius Caesar, Pompey and Crassus has also been wrongly called a “triumvirate,” but they never had the title tresviri, and held no office under that name.
See T. Mommsen, Römisches Staatsrecht (1888), ii. 594-601, 638, 601, 718; J. Marquardt, Römische Staatsverwaltung (1885), iii. 347.