A military tribune (Latin tribunus militum, "tribune of the soldiers") was an officer of the Roman army who ranked below the legate and above the centurion. Young men of Equestrian rank often served as military tribune as a stepping stone to the Senate. The tribunus militum should not be confused with the elected political office of tribune of the people (tribunus plebis) nor with that of tribunus militum consulari potestate. Early Rome The word tribunus derives from tribus, "tribe". In Rome's earliest history, each of the three tribes (Ramnes, Luceres, and Tities) sent one commander when an army was mustered, since there was no standing army. The tribunes were commanders of the original legion of 3,000. By the time of the Greek historian Polybius (d. 118 BC), the tribunes numbered six, and they were appointed by the consuls. However, the process by which tribunes were chosen and assigned is complex and varies at different times. Republican period In the Republican period, there were six appointed to each legion. Authority was given to two at a time, and command rotated among the six. Tribunes were men of senatorial status appointed by the Roman Senate. To attain the position of tribune, one only needed to be a member of the ruling class. By 311 BC the plebeians acquired the right to elect sixteen tribunes of the soldiers, that is, four out of the six tribunes assigned to each of the four legions that formed the Roman army. Previously these places had been for the most part in the gift of consuls or dictators. Additionally, in the early Republic, another type of military tribune was sometimes chosen in place of the annually elected consuls to be the heads of the Roman State. These are known in Latin as tribuni militum consulari potestate ("military tribunes with consular authority"). At the time only patricians could be chosen as consuls, but both patricians and plebeians could be elected as tribunes with consular authority. Instead of the usual two consuls, between four and six military tribunes were elected for the year. The reasons for this choice are obscure, though Livy often cast the decision according to the class struggles he saw as endemic during this period, with patricians generally favoring consuls and plebs the military tribunes. The office of "consular tribune" eventually fell out of use after 366 BC. After the Marian reforms After the Marian reforms