Credit for permanently fixing the names and numerals of the legions belongs mainly to Augustus. Following the civil wars of 49–31 BC, Augustus reorganized and reformed the legions as a standing army. Henceforth, legions would get a permanent number and, over time, a name. As such, Augustus created, if not a system, then certainly guidelines which codified a series of earlier practices developed during the Republic and innovations from the civil wars. Frustratingly, there is no documentation in which Augustus, or any later emperor, lays out the complete rationale behind assigning the legions their numerals and names. It is important to note that this was not a system in the modern sense, as there were seemingly numerous exceptions.
Their number is legion
The numbering of the legions was a tradition dating back to the early days of the Republic when each year four legions were raised. These were numbered I to IV according
