Late Roman Attic helmets

[Flavivs Aetivs]

The depictions of Attic helmets have actually been confirmed to be Intercisa IV Ridge Helmets. Just saying.

It's artistic liscense, probably. The artist is most likely representing the Helmet as if the Neck Guards were still attatched, like on previous models. Maybe some sort of transition between the Itnercisa and earlier Itallics?

Much Artistic liscense was taken on the Arch of Constantine, notably in the depiction of Lorica Segmentata, which was a stylization just like depictions of Musculata on other reliefs of that era. (Although, interestingly enough, some sets of Segmentata might have survived to constantine's time, depending on what was in the reserves.)