When Did The Roman Army Standardize Using Plate Armor?

[Caratacus]

Ah well - we're going to have to differ on that one. Mail armour was in use from at least the 4th CBC and this was probably true for scale armour as well. There must have been some reason for the introduction of the segmentata armour, and likewise for the phasing out of this type as well. The maintenance of the plate armour was quite intensive and had to be carried out by expert armourers - which would have been a negative factor from the get-go. Squamata and hamata could be easily, if temporarily, repaired 'in the field'. Given these drawbacks, why was segmentata brought into service at all? I think that we have to ask the question as to why this segmentata armour, in its various forms, which had been in use for around 3 centuries, was 'suddenly' withdrawn from service.

I would question your contention that scale armour was heavier that segmentata, whilst agreeing that mail armour was certainly heavier. In fact, the latter was considerably heavier, which would suggest to me that it would not have been the preferred type, given a choice. David Sim has carried out extensive work on reproducing mail armour, which has shown that a mail coat took a long time to manufacture - much longer than a segmentata suit. Again, I ask the question, what prompted this (relatively) sudden change? The only consistent thing that makes any sense to me is that there was some sort of fundamental change in the enemies that the Roman infantry faced and therefore in the tactics that had to be used in reply.