commanded the tribal contingents in the army of the early Roman state. Subsequently six were appointed as the most senior officers within a legion, and at least five years' previous military experience was expected. They were equestrians (see equites), though some were the sons of senators, and occasionally senior men took the post. The tribunes of the first four legions recruited each year were elected by the people, while those for additional legions were chosen by the commander. Two tribunes acting in rotation commanded a legion for two months, but they had no specific tactical responsibilities and their duties encompassed the general welfare and discipline of the troops and supervision of the camp. Under Caesar, as legati were used more extensively, tribunes declined in importance.
In the imperial period one of the six legionary tribunes was normally a senator (tribunus laticlavius), a young man early in his career, probably holding the post for one year. The other five tribunes were equestrians (tribuni angusticlavii) who were often more experienced in army life. By the mid-1st cent. ad a pattern had emerged in which many equestrians held at least three military posts—prefect of a cohort, tribunus militum, prefect of an ala. Tribunes also commanded individual cohorts in the urban troops, and sometimes larger milliary cohorts or cohorts of Roman citizens, while by the late empire the term was employed to describe officers of the imperial guards, the legions, vexillationes and auxilia of the field army, and also the cohorts of the limitanei. See cursus honorum.