Tribune (from the Latin: tribunus; Byzantine Greek form τριβούνος) was a title shared by 2–3 elected magistracies in the Roman Republic. Tribunes had the power to convene the Plebeian Council and to act as its president, which also gave them the exclusive right to propose legislation before it. Also, the tribune could summon the Senate and lay proposals before it. The tribune's power, however, was only in effect while he was within Rome. His ability to veto did not affect provincial governors, and his right to sacrosanctity and to help only extended to a mile outside the walls of Rome. In about 450 BC the number of tribunes was raised to ten.

Because it was legally impossible for a patrician to be a tribune of the plebeians, the first Roman emperor, Caesar Augustus, was offered instead all of the powers of the tribunate without actually holding the office (tribunitia potestas). This formed one of the two main constitutional bases of Augustus' authority (the other was imperium proconsulare maius). It gave him the authority to convene the Senate. Also, he was sacrosanct, had the authority to veto (ius intercessionis), and could exercise capital punishment in the course of the performance of his duties. Most emperors' reigns were dated by their assumption of tribunitia potestas, though some emperors, such as Tiberius, Titus, Trajan, Marcus Aurelius etc, had already received it during their predecessor's reign. Marcus Agrippa and Drusus II, though never emperors, also received tribunitia potestas. By extension from the technical Roman governmental usage, some modern politicians have been called "tribunes of the people."

Plebeian Tribune

In the year 494 BC, the city was at war,Abbott, 28 but the Plebeian soldiers refused to march against the enemy, and instead seceded to the Aventine hill.Holland, 22 The Patricians quickly became desperate to end what was, in effect, a labor strike,Holland, 22 and thus they quickly agreed to the demands of the Plebeians, that they be given the right to elect their own officials.Abbott, 28 The Plebeians named these new officials Plebeian Tribunes (tribuni plebis), and gave them two assistants, the Plebeian Aediles (aediles plebi).Byrd, 31Holland, 5

Since the Plebeian Tribunes and Plebeian Aediles were elected by the Plebeians (commoners that also owned land) in the Plebeian Council, rather than by all of the People of Rome (Plebeians,the aristocratic Patrician class and The "Head Count" (which were not land owning people)), they were technically not "magistrates". While the term "Plebeian Magistrate" (magistratus plebeii) has been used as an approximation, it is technically a contradiction.Abbott, 152 The Plebeian Aedile functioned as the Tribune's assistant, and often performed similar duties as did the Curule Aediles (discussed above). In time, however, the differences between the Plebeian Aediles and the Curule Aediles disappeared.