Historic Earth some time around 50-60 BC. But with low level magic.
After their recent defeat at the hands of a Gallic tribe, Consul Gaius Julius Caesar has taken the unusual move of ordering a new levy to fill the ranks of Legio XIIII and bring it back up to full strength, rather than disbanding the Legion after its shameful performance. The core of hard-bitten veterans that remain will have to bring the new recruits up to speed so that they can win back their honour!
You are one of these new recruits, known as a "Tyro" until you finish your training.
Each Century has 80 soldiers and 20 support staff. I figure each squad or "Contubernium" is lead by a Decanus (from whence the word "Dean" derives), and has 8 legionaries and 2 ancillaries staff for doing cooking, first aid, hauling baggage and perhaps some other nefarious stuff.
A scene from your early days in training:
With hair long and his beard unkempt from mourning, Caesar addresses the newly formed Legio XIIII:
"The defeat you suffered was not your fault, but was caused by gullibility and lack of leadership of Senator Sabinus. No stain remains upon you. You have discharged your duty with exemplary honour. Those of the 14th that made it back to the walls of Atuatuca with the Eagle took the Noble course and fell on their swords. Whilst those of you who endured two nights of harrowing pursuit to join with the Fort at Luxemberg and Legate Quintus Ciceros' Legio 7, you… why you are the heart of this legion. Already you are Legend in Rome. Your stalwarts were the backbone of Luxemberg. You make me proud to call you my own….
In recognition of this, you shall be the First File of the reformed Legio 14. And every veteran of Atuatuca will receive 200 Sesterces in recognition. All Decanii will receive 400. And all Centurions 2000." HUGE CHEERING.
"As for the rest of you… " He slowly looks around, "New recruits. Mostly Celts. Some would call you scum. Some would say that you are not worthy to be in this man's Legion. To wear the lorica of a legionary. To bear arms. But you are noble Aedui. The Lions of Gaul. Staunch allies of Rome since we came to this land. Back to back we have fought against your enemies and always we have known that our flanks were secure when together we marched out. I name all 300 of you Citizens of Rome. The first of Gaul to be so honoured. Know that all of Rome is watching what you do. I salute you!"