Evidence for legionary vs auxiliary helmet patterns

[Matthew Amt]

I keep hearing an argument that early imperial legionaries wore mostly iron helmets and that auxiliary soldiers wore mostly copper alloy.

Good heavens, you do? Very odd! There was a time when Imperial-Gallic type G and its close brethren were THE helmet used by legionary reenactors, while auxiliaries were all in brass styles, but diversity has long since conquered most of that.

However, I'm not sure we can go the other way, that it was *usually* iron for auxiliaries and brass for legionaries. The answer is most likely somewhere in the middle. The usual firm gray area!

I have no first hand experience with making a helmet. But in a general sense, brass/bronze are easier to work than steel, and require less heating temperature. That could be a contributing factor.

Not necessarily. Iron can be worked hot, and in such a state is very forgiving. Cracks can be forge-welded shut, to a certain extent. Copper alloys, on the other hand, must be worked cold, with frequent annealing to avoid metal fatigue and cracking. In either case, the temperatures needed for either metal are in the same range, easily attained by the forges of the time. Obviously, armorers who worked with brass and bronze were highly skilled, since I have rarely seen any evidence for cracks or patches due to manufacturing on Roman helmets. Same with the iron ones. So they knew what they were doing and it wasn't any inherent trouble for them. Brass and bronze can also be spun on a lathe to make helmets, bosses, and other items, which was not generally practical for iron objects because of slag content.

This is something that I tend to put down to fashion. Italy seems to have retained a tradition of bronze-working well into the late Empire--note the large numbers of bronze domestic items found in Pompeii, for instance. By comparison, Gaul and other provincial areas were known for their iron work, though they were certainly capable of producing copper alloy items as well.

Matthew