The Lorica Segmentata
The first illustration in White Horse, Black Raven is of a Roman legionary wearing the type of body armor common during the era of Roman called the Principate, roughly 27 BC - 284 AD. It was constructed of a series of soft iron plates held together with leather straps and fastenings made of copper alloy. It weighed approximately twenty pounds and provided excellent protection for the upper arms and shoulders. Unfortunately, it also was a little restrictive for deep breathing.
The segmentata could fit a range of body sizes and it could collapse down on itself for easier packing and transport. The strips of iron plating could be replaced without too much difficulty if they were damaged. This made the armor a little less expensive to maintain. On the other hand, the copper of the fittings set up a chemical reaction with the iron plates causing corrosion, and they seemed to break easily. There a many examples of fittings found in Roman military sites.
Archaeologists and historians had known of the segmentata for centuries but had never known how they were constructed. Then the bits and pieces of six segmentata were found in a box buried near a fort on Hadrian's Wall. From these remnants archaeologists were able to reconstruct the armor.
The Alemanni did not make their own armor. Instead it would have come as spoils of war, taken from slain Roman soldiers or from armories of captured forts and military bases.