The second version is that of Caesar, which is quite different. It is an army of undifferentiated heavy infantry, fighting in cohorts, supported mostly by non-Roman auxiliary light infantry and cavalry. Moreover, while the Polybian legion was raised by conscripting Rome’s landowning citizens (the so-called assidui), the Caesarian legion is normally described as a volunteer force, fighting for pay and recruited mostly from Rome’s landless poor.
Maniple to cohort
How did we get from one version to the other, from the Polybian to the Caesarian army? We don’t really know – evidence for the late second and early first centuries BC is thin, especially when it comes to Rome’s army. But the conventional explanation for all these changes pins the responsibility on Gaius Marius, consul for the first time in 107 BC. It was the ‘Marian reforms’ that put Rome’s army on the road to professionalism, changed from maniples to cohorts as the unit of tactical organization, standardized equipment and weaponry, and perhaps even modified the heavy javelin, the , making it more difficult for the enemy to hurl back in battle. According to this version (which is still, by and large, the one found in textbooks and taught to students), it may not have been Marius who transformed the Roman soldier from upstanding citizen-farmer to grasping mercenary, ready to back his generals in civil war and desert to the highest bidder, but Marius certainly started the process. is usually appealed to:
