Cataphracts were almost universally clad in some form of scale armor ( "Falidotos", equivalent to the Roman Lorica squamata) that was flexible enough to give the rider and horse a good degree of motion, but strong enough to resist the immense impact of a thunderous charge into infantry formations. Scale armor was made from overlapping, rounded plates of bronze or iron (varying in thickness from four to six millimeters), which had two or four holes drilled into the sides, to be threaded with a bronze wire that was then sewn onto an undergarment of leather or animal hide, worn by the horse. A full set of cataphract armor consisted of approximately 1,300 or so "scales" and could weigh an astonishing 40 kilograms or 88 pounds (not inclusive of the rider's body weight). Less commonly, plated mail or lamellar armor (which is similar in appearance but divergent in design, as it has no backing) was substituted for scale armor, while for the most part the rider wore chain mail. Specifically, the horse armor was usually sectional (not joined together as a cohesive "suit"), with large plates of scales tied together around the animal's waist, flank, shoulders, neck and head (especially along the breastplate of the saddle) independently to give a further degree of movement for the horse and to allow the armor to be affixed to the horse reasonably tightly so that it should not loosen too much during movement. Usually but not always, a close-fitting helmet that covered the head and neck was worn by the rider; the Persian variants extended this even further and encased the wearer's entire head in metal, leaving only minute slits for the nose and eyes as openings. Ammianus Marcellinus, a noted Roman historian and general who served in the army of Constantius II in Gaul and Persia and fought against the Sassanid army under Julian the Apostate, described the sight of a contingent of massed Persian cataphracts in the 4th century: