Reconstruction of Felt Subarmalis and Linen Pteryges

[Tarbicus]

the mail won't keep the damp out, but the leather will.

And likewise, the leather will not only keep the sweat in, it'll also create more sweat.

I think I've seen one painted depiction of Roman pteryges in brown, all of the rest are red, blue, etc, and mostly white. Pteryges are protection not decoration, and for leather to be flexible enough it has to be fairly thin, as opposed to multiple NOT GLUED layers of linen which will retain flexibility in those areas most needed - the upper arms and upper legs.