Just starting- C3rd Roman

[Crispvs]

I am not convinced that there was such a radical change in equipment between the mid third century AD and the early fourth century AD, when compared with other periods and I think too much is read into the adoption of new helmet and belt type. Certainly, as Robert says, there will have been reasons for the adoption of ridge helms, but the difference between the soldiers of both ends of this spectrum is surely no more radical than the difference between the soldiers at either end of a similar length period in earlier periods.
If you were to take an example of a soldier of the period of the invasion of Britain in AD43 and contrast him with a soldier of fifty years later, you would see different sword and scabbard types, different belt styles, probably different helmet styles and possibly different footwear styles. Similarly if you were to contrast a soldier of the mid second century AD with another of fifty years later, you would see differences in sword and scabbard furniture, helmets, belts and clothing too. The differences seen in these two examples would be no more but no less radical than the differences between soldiers of the mid third and early fourth centuries.

Crispvs