Roman Gallic Helmet with Red 18G-PP Roman Gallic Helmet with Red 18G PP. These were additionally lettered within each group to show significant variations in date and methods of construction. He also classified approximately 30 different types of check guards, which were in use with these and other varieties of Roman Helmets. His book “The Armour of Imperial Rome” gives detailed descriptions of his classification system but it is currently apparently out of print and rarely available so consequently is expensive to buy through dealers. Most of the helmets normally identified as used by legionaries have some form of plume or crest holder on the crown of the helmet but the precise method of attachment varies depending on period, location made and the type of helmet. The earliest forms known were probably similar to those depicted on early Greco-Etruscan pottery. The plumes and crests, based on the styles depicted on the pottery, appear to have used either feathers or naturally coloured horse-hair. Imperial-Gallic, based on the type of helmet used by the Gaul’s. These were more decorated than earlier varieties with embossed “eyebrows”, had a re-enforced peak and a ridged extension at the back as a neck-guard. These were initially probably made by Gallic smiths so retained the original influence in construction and design and stretched in use from the late 1st century BC through to the early 2nd century AD