According to Robinson (The Armour of Imperial Rome, p. 107-111), the cavalry sports helmet, covering the face and resembling a theatrical mask, was worn by Roman auxiliary cavalry in equestrian exercises known as hippica gymnasia. Along with these elaborate helmets would be worn a special shield, an embroidered tunic and possibly thigh-guards and greaves, all of which would contribute to the splendor of the display. These exercises most probably accompanied religious festivals celebrated by the Roman army and were also put on for the benefit of visiting officials. Arrian, a provincial governor under Hadrian, and the only surviving source of information about the hippica gymnasia, describes how the horsemen were divided into opposing teams, taking turns to attack and defend.
A small series of masks representing females survive. These most probably would have been worn by the team representing Amazons in re-enactments of the wars between Greeks and the Amazons, an unfailingly popular theme for Greek and Roman artists, and a good subject for display.