Illustrations of Sassanid Persian Clibanarii

[Urselius]

The Arlon cavalrymen are shown wearing what appear to be segmented plate pauldrons over mail shirts. The possibility of plate being worn over mail defences for Roman cataphracts is thereby strengthened.

I had forgotten about that too, although I have to say that that is the first half-way decent picture of it that I have seen. It could bear the interpretation that you put upon it but, that said, I am not sure that it helps overmuch. It is, as far as I know, unique, and the fact that some 1st century(?) auxiliary cavalrymen may have substituted mail shoulder-doubling with another form of protection, possibly in metal, probably has little bearing upon the form of armour worn by elite specialist heavy cavalry, arising out of a different tradition, three centuries later. I repeat that what is needed to support the theory that clibanarii wore plate-over-mail is some evidence that the ancient descriptions are of predominantly mail-clad warriors further protected by additional metal plates and, as far as I am aware, we do not have that.

I think that your 'burden of proof' approach is too rigorous. What we have are a few short descriptions, open to variations in translation and interpretation, one image - this apparently a doodle by a talented amateur artist - and some renditions of disjointed armour on weathered monuments and recopied manuscripts. Not much to go on. What I am trying to do is come up with some ideas about how Roman cataphract armour could have worked and make some sort of ranking as to possibility/probability. With that limited goal in mind the Arlon bas relief is relevant as it gives a precedent (even in Dan's restricted use of the term) for Roman use of plate-over-mail defences. In my opinion this strengthens the plate-over-mail scenario and weakens that of mail-and-plate.