Above is pic of a roman helm from the British Museum (I think) I am not dead sure, but I "think" this shows a steel spun bowl, overlaid with a fair amount of thin bronze. Or maybe gold...it seems awfully well preserved for bronze.
After assembling all the disparate pieces, I was left with something like this. The bowl was way too thick for me to even think of doing that "bellows" effect at the back of the neck...it was battle grade at about 10 gauge....and 8 gauge near the bottom. Too heavy to even think about wrinkling the metal.
From the front, it looks not too bad. The lion was a sort of after thought.....I suppose I should have put two of them up there, one over each eye. But as I said, I was in a hurry, and only had the one lion.
There you go your excellency...a cute little battle helmet.
The emperor Antonious Pius's blog is here....http://antoninuspius.blogspot.com/