Roman helmets: Imperial Gallic/Italic and Ridge - comparisons and sources

[Condottiero Magno]

A Ridge helmet is significantly easier to build, this could easily justify its adoption, despite the different kind of structure is conceptually more subject to breakage, especially in a time of constant crisis that led to an increasing preference for the immediacy of the cavalry on the solidity of heavy infantry.

While a ridge helmet is easier to build, I'd like to see some evidence for it being "conceptually more subject to breakage."

For the fact that putting side by side two metal pieces you are creating a breaking point? This is not something similar to Lorica Segmentata where there is a partial overlap and the blow is absorbed by two or even three metal layers without being able to find a breaking point, its two or more metal parts that are flanked, with some sort of junction that will absorb the shock, creating the weak point.

As said, the romans well know the ridge helmet, but they adopted it only late, as they started to adopt the long sword for infantry only late. And, they adopted it in a moment in which they created a big amount of equipments. Considering how that helmet is done, and the context, it is not difficult to think that they sacrificed the quality for the quantity.

Not how ridge helms and spangenhelms work...

Montefortino helmets were in use longer than Gallic types, so what's your point?

Spatha is just another name for a sword, just like gladius, and earlier gladii could be as long as spathae.