Use of Leather as armor

[Sean Manning]

Dreaming about 150.000 Roman legionaries + 150.000 Roman Auxiliaries = 300.000 men all clad in iron shining Hamata or Segmenteata armors is not only pure madness but also one of the most strange Fantasy tales ever invented!

Diocle, multiplying numbers as high as possible is a tradition which goes back to Herodotus, but it makes for better rhetoric than scholarship. Here is another calculation which you might want to consider.

For every hundred thousand soldiers in mail (nobody says that every Roman soldier wore mail) let us assume that their armor took six men a month to make (this is vaguely reasonable based on costs in the 14th and 15th centuries where industry was starting to approach Roman sophistication; your Osprey book assumes that a man could weave the armour in a month, but the real work was probably in making the wire). But each armour lasts a hundred years (plenty of medieval and early modern examples) so each year six thousand months of work are needed to replace the armour which is lost or worn out (100,000 loricae x 6 months of work/lorica % 100 years/lorica = 6,000 months of work/year). Five hundred men working full time could supply those hundred thousand soldiers (6000 months of work/year % 12 months/year).

Somewhere between 100,000 and a million loricae hamatae were needed by the Roman army, depending on whether you think only a few soldiers wore mail, or most soldiers plus some of their horses and servants (one horse armour would be as much work as several armours for men). So out of an empire of tens of millions of people, 500-5,000 people might have been required to make mail for the army. If you assume that each shirt of mail only lasted ten years, you could get a number as high as 50,000 workers but only by always choosing the highest possible number.