of 107 BC (subsequently further formalised by the emperor Claudius) created a professionalized military system, legions were commanded by a legionary legate (legatus). Six tribunes were still posted to a legion, but their duties and responsibilities had changed, becoming more a political position than a military rank. The second-in-command to the legate was the tribunus laticlavius or 'broad-stripe' tribune (named after the width of the stripe used to demarcate him on his tunic and toga), usually a young man of senatorial rank. He was given this position to learn and watch the actions of the legate. They often found themselves leading their unit in the absence of a legate, and some legions were permanently commanded by a broad-stripe tribune, such as those stationed in Egypt, as an Augustan law required that no member of the Senatorial Order ever enter Egypt. In contrast to the broad-stripe tribune, the other five 'thin stripe' tribunes were lower in rank, and were called the tribuni angusticlavii. These 'officer cadets' were men of equestrian rank who had military experience, and yet had no authority: they were allowed to sit on a court martial but they held no power in battle. Most thin-stripe tribunes served the legionary legate, yet a lucky few (such as Agricola) were selected to serve on the staff of the provincial governor. According to Tacitus, they did not always take their appointment as seriously as they might, contrasting Agricola's tribuneship to his peers by saying "[Agricola did not], like many young men who convert military service into wanton pastime, avail himself licentiously or slothfully of his tribunitial title, or use his inexperience to spend his time in pleasures and absences from duty". Principate Under Augustus, the five equestrian tribunes were sometimes promoted from the rank of centurion, and might advance to a command in the auxiliary cavalry or Praetorian Guard. See also List of Roman tribunes References Military ranks of ancient Rome Ancient Roman titles Cursus honorum