The hippika gymnasia (, "horse exercises") were ritual tournaments performed by the cavalry of the Roman Empire to both practice their skills and display their expertise. They took place on a parade ground situated outside a fort and involved the cavalry practicing manoeuvring 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. The riders practised complex manoeuvres with dummy weapons, alternately attacking and defending, and displaying their horsemanship and courage to onlookers. Clothing and armour The participants in the hippika gymnasia would have been an impressive sight for those who saw them; as one writer has put it, "a cavalcade of richly armoured horses and men – who in their masked helmets with silvered faces looked like divine beings." The riders wore brightly coloured tunics – which seems to have evolved into decorated bronze armour by the 3rd century – and very ornate greaves and helmets with face masks. As Arrian described them, Substantial archaeological evidence has been found of such "sports equipment", as it has been dubbed. A hoard of cavalry display armour dating to the 3rd century AD was discovered at Straubing in Bavaria in 1950. It included extraordinarily elaborate horse armour, greaves, helmets and other pieces of armour. Many more "sports helmets" have been recovered from other locations. They were made from a variety of metals and alloys, often from gold-coloured alloys or iron covered with tin. They were decorated with embossed reliefs and engravings depicting the war god Mars and other divine and semi-divine figures associated with the military. One of the Newstead Helmets from Scotland, for