Christies Late Roman helmet: 1 or 2?

[Flavivs Aetivs]

As was mentioned, the only way to truly determine its authenticity is a test of the metal content, and a chemical test of the corrosion would determine whether or not it was natural.

Jens has presented a strong argument for its authenticity, but I personally still have my doubts.

A reconstruction of the helmet would certainly be useful in determining its effectiveness and other characteristics.

As for its dating, all we know about it is that its from a private collection. We have no context in which it was found, ergo we cannot accurately date it to anything more than the 280-410 period (Richborough to River Maas Helmets, all Ridge Helmets).