Tribune (Lat. tribunus), originally, a Roman officer who presided over one of the three tribes, Ramnenses, Titienses, and Luceres. In the long course of Roman history the name came to be applied to various officers with widely different powers and duties. As originally constituted, the Roman legion consisted of 300 cavalry and 3,000 infantry; over the cavalry presided an officer called tribunus cele-rum, and over each 1,000 of the infantry a tribunus niilitum. The tribuni celerum disappeared with the overthrow of the monarchy. The office of the tribuni rnilitum continued through the whole course of Roman history, but the manner of their appointment, their number, and their powers and duties were often changed. " Tribunes of the soldiers, with consular power," were first chosen in 444; and in succeeding years sometimes consuls and sometimes tribunes with consular power were chosen. In 367 the office was abolished, and thereafter only consuls were chosen. The name "tribune of the Servian tribes" is applied by historians to the administrative chiefs of the local tribes which were gradually added to the Roman commonwealth; it is supposed by Nie-buhr and others that the tribunes of the treasury of later times were similar to them. - The " tribunes of the people " were the most important of all the officers bearing the name.

They were first appointed after the secession of the commonalty to the Mons Sacer, in 494. They were empowered to protect the plebeians . against the usurpations of the patrician magistrates, and their persons were declared sacred and inviolable. They appear to have been originally two in number, and to have been' elected for one year by the comitia of the centuries. In 471, by the Publilian law, the election was given to the comitia of the tribes. About the same time the number was increased to five, and from 457 B. C. until the end of the empire ten tribunes were annually elected. None but plebeians were eligible for the office; so that if a patrician were desirous of filling it, he was obliged to renounce his own order. The early incumbents of the office exercised authority within the city limits and over one mile of adjacent territory; the doors of their houses were ordered to be open day and night, and all persons taking refuge there were assured of protection. For similar reasons they were forbidden to absent themselves from the city for a whole day.

Although their lawful power was originally merely auxilium, or the right to afford protection, they assumed within a few years the right to convoke the senate, and in 454, after a long struggle, secured the appointment of the three commissioners whose labors led to the codification of the laws of the twelve tables. During the second decern vi-rate the tribunate was suspended, but with the overthrow of that oligarchv it was restored with augmented powers; and as the tribes now included patricians and their clients as well as plebeians, the tribunes became the protectors of all classes of citizens. They now also acquired the right to be present at the deliberations of the senate, and to take part in its discussions, although not allowed to pass within the doors of the senate house; and hence they gradually assumed the privilege of intercession against any action taken by a magistrate, and by the interposition of their veto were enabled to annul any decree of the senate or stop any law, without cause or reason assigned. On the other hand, they sometimes interfered to compel the consuls to comply with decrees of the senate. About 132 B. 0. they became senators by virtue of their office.

They also assumed the right of commanding their viatores or attendants to seize a refractory magistrate, and imprison him, or even to hurl him from the Tarpeian rock. They possessed the exclusive power of proposing plebiscita to the comitia of the tribes; and after these had obtained by the Hortensian law, 286 B. 0., the binding force of laws, the tribunes became a magistracy for the whole Roman people, in opposition to the senate and the oligarchical elements in general, although they had nothing to do with the administration of the government. Subsequent to 394 B. 0. the veto of a single tribune sufficed to render a resolution of his colleagues void; and it was not until Tiberius Gracchus introduced the practice of appealing to the people to remove a tribune who obstinately adhered to his veto, that the harmonious working of the system was restored. During the latter period of the republic Sulla, in his reform of the constitution on an aristocratic basis, gave the tribunes merely the jus auxiliandi which they originally possessed. Pompey restored them to their former power, but under the empire their privileges became much restricted, although until the 5th century they continued to have the right of intercession against decrees of the senate and on behalf of oppressed individuals.

The emperors, though patricians, found it necessary to be tribunes, and the tribunicia potestas, conferred by the senate upon Augustus and his successors, was considered an essential part of the imperial dignity. - After Diocletian there was an officer called tribunus voluptatum, who was the superintendent of public amusements.