\"Celtic\" military technology and the Romans

[Urselius]

The Byzantines used doubled mail camails, and some 12th century illustrations seem to show lamellar worn over mail.

Example please. I've had a look through a lot of illustrations and most of them are too ambiguous to conclude that they are depicting lamellar worn over mail.

Also, from an earlier post on this site concerning a description of cataphract armour:

Ammianus Book 16 ch. 10 -8

"thoracum muniti tegminibus et limbis ferreis cincti" is usually translated as "protection of iron breast-plates, and girdled with belts of iron". However, limbis is not a usual word for 'belt' in Latin, and literally means "piping" or "border/edge". Could be the description of some sort of combination armour for the torso.

What does this have to do with mail?

You had just written this:

"This is unlikely. We know that they wore both kinds of armour but I can't think of anything to indicate that both were worn at the same time. Even the Byzantines never wore both until very late in the period - about when the Europeans started layering mail with other kinds of armour. "

Forgive me, but what I wrote seemed to be directly relevant to your comments - ie the possibility that Roman cataphracts wore double layered armour for the torso.

Double layered face-covering camails are directly described in a number of Byzantine military treatises. There are depictions from the 11th century showing Byzantine soldier saints wearing lamellar klivania with mail sleeves and mail skirts. Where klivania are shown with splint sleeves and mail skirts I would say that separate mail skirts (kremasmata) are being shown. However, when mail is shown at sleeve and skirt the most logical interpretation is that the klivanion is being worn over a complete mailshirt.

Before the Battle of Sirmium the Byzantine general Andronikos Kontostephanos is described by the historian Choniates as "donning his mailshirt and then the rest of his armour", This is not completely overt, but it suggests that a klivanion is being worn over the mailshirt.