Christies Late Roman helmet: 1 or 2?

[markusaurelius]

"iron helmets of great age can be wonderfully well preserved and that, therefore, good preservation does not constitute a hindrance to authenticity in itself".

I don't think anyone is disputing that their state of preservation means they may not be authentic. One only need to look at the other helmets of the period, some of which are in great condition.

What the analysis of the metal (if any is left) and the corrosion layer will tell us is if the "Rust" was artificial, or consists of the many iron ore composites that are created from corrosion. An artificially "Rusted" helmet would likely show signs of the chemical used to age it and not reveal the types of minerals and materials that comes with a corroding piece of iron. It may even reveal some details of the soil they were in should they be found to be authentic.