Decemvirs (Lat. decemviri, ten men), the title of several bodies of magistrates in ancient Eome. The decemviri legibus scribendis, appointed to digest a written code of laws, were first elected in 451 B. C. The tribune 0. Teren-tius (or Terentillus) Arsa, after' a violent exhibition of the grievances of the plebeians and the usurpations of the patricians, about 460 proposed the appointment of ten commissioners to digest a regular body of laws which should be binding alike upon every citizen. This compromise between the two orders was accomplished after nine years of continued struggle. An embassy was sent to Greece to obtain information concerning the laws of the different states, and particularly concerning those of Solon; and after its return ten distinguished patricians were appointed for a year, with supreme power, to frame the new laws. They entered upon their work with zeal and diligence, and exercised their power with justice, impartiality, and moderation, each presiding in turn day by day, and he only using the fasces. The new laws, engraved on ten tables of brass, were placed in the forum and sanctioned by general acclamation, as well as by the sacred rites of the augurs.

But two additional tables being required, a new decemvirate was elected for the next year, in which the patrician Appius Claudius managed to be reelected, and to introduce a few plebeian members. He thus became the favorite of the people, while aiming to become their master. The laws were completed, and afterward known under the name of " laws of the twelve tables," and were admired for their wisdom, which, according to Cicero, surpassed that of all the books of philosophy. But now the decemvirs changed their conduct, exercised their power over all classes with oppressive rigor, and by terror maintained themselves in office after the expiration of their term. The attempted rape of Virginia by Appius Claudius, under the guise of a public judgment, and the killing of the virgin by her own father to save her honor, brought about the overthrow of this decemvirate. - The decemviri litibus judicandis were a judicial magistracy, established at an uncertain date. Their authority extended over matters relating to persons and taxable property, and they had the management of the subhastationes.

Under the emperors they were the presidents of the centum viral court. - The decemviri sacrisfaci-undis (or more briefly sacrorum) were a college of priests for the interpretation of the Sibylline books, established about 368 B. C, instead of the ancient patrician duumviri; they were chosen for life, partly from the patrician, partly from the plebeian order, and had the management of the Apollinian and secular games. At a later period their number was increased, probably by Sulla, to 15.