Tribunus laticlavius
In the Roman army of the late Republic and the Principate, the  ("broad-striped tribune") was one of the six military tribunes in a legion. Usually, it consisted of young men around age 20 who belonged to a wealthy family or were friends with the legate. The position of  was the first step on the . Overview 
The tribunus laticlavius were second in command to the , the legion's commander. They were also above the other five  and later the . It was common for the tribunus laticlavius to be a Roman noble younger than 25 years old, usually around the age of 20. They were commonly either part of the richest families in Rome or a close friend to the legionary commander. It was also common for the tribune to have no previous military experience. Members of the  were part of the senatorial aristocracy. It was common for the tribune to return to Rome and run for a political office, usually a quaestorship after two or three years as a tribune. The position was the first step of the traditional . By the middle of 250s AD, at the earliest, the post of the  had disappeared from the Roman army, following the general trend of removal of the senatorial class from military commands. See also 

 List of Roman army unit types
 Centurion
 Legatus 
 Primus Pilus
 Decanus
 
 Tribune

References 

Military ranks of ancient Rome