H.R.Robinson Helmet Typology

[caiusbeerquitius]

The Dragendorf 'classification' is entirely visual and depends on simple shape comparison. It is also not exhaustive, as there are 'supplementary' classifications due to Curle, Ritterling, Webster, Ludovici, etc for forms that Dragendorff didn't know about! In short, 'samian' pottery is a far simpler proposition than what we are faced with here for helmets.

That´s not what I meant. I meant applying a simple number to the helmets / helmet types. As soon as a helmet is a double add a/b .
Worked nicely for the Guttmann collection.