Evidence for legionary vs auxiliary helmet patterns

[Peroni]

Certainly a lot of this is down to the classification system constructed by H R Robinson. (Simple and brass = auxiliary use - Fancy and iron must be legionary(?))

As you point out Tim, we have grave finds of 'Gallic' iron helmets from provincial burials such as Idria Pri Baci, Verdun etc so iron helmets of Robinson's 'Gallic' type were certainly in use by auxiliary soldiers. Which, makes perfect sense, as this helmet was developed from Gaulish (Port Bei Nidau) type helmets in the first place!