At Cannae, in Southern Italy, the Army of the Roman Republic faced Hannibal in the 2nd Punic War.
At the time a Roman citizen could not “join” the Army; it was an honor reserved for those of property and standing. It was expected of those with property and standing. It was not expected of the poor. It would be another hundred years before Gaius Marius allowed “ordinary” citizens to enlist.
At the time of Cannae the standard requirements to become a Roman soldier were very…
Source: Marius and the Volunteer Army