Their were worn during tournaments, called 'hippica gymansia'.

The hippika gymnasia (Greek: ἱππικὰ γυμνάσια, "horse exercises") were ritual displays or tournaments performed by the cavalry of the Roman Empire to display their skill and expertise. They took place on a parade ground situated outside a fort and involved the cavalry practicing manoeuvrings and the handling of weapons such as javelins and spears The riders and their mounts wore highly elaborate armour and helmets specially made for display purposes, decorated with images from classical mythology. Such tournaments served several purposes, improving the riders' skills, helping to build unit morale and impressing dignitaries and conquered peoples.

The Romans maintained substantial cavalry forces to support their legions. The elite of the cavalry, the alae, were expected to perform complex manoeuvres that required extensive training. The role of the cavalry was described in the 2nd century AD by the Roman writer Arrian in his Ars Tactica, a (possibly theoretical) work in which he described how the legions and auxiliary troops could be organised to defeat an enemy. He recorded the hippika gymnasia in considerable detail, though – as he was writing in Greek – we do not know the Latin name of such events.[4] The riders practised complex manoeuvres with dummy weapons, alternately attacking and defending, and displaying their horsemanship and courage to onlookers.