cardiophylax

noun1

1. •
   A piece of body armour—originally a metal breastplate or pair of plates—worn in classical antiquity to protect the region of the heart. Typically circular or square discs, fastened by leather straps, used in Italy from the Villanovan and Etruscan periods (7th century BCE) and later by Roman Republican legionaries and gladiators such as provocatores.

   • On the other side of the cardiophylax, the surviving details indicate riders, possibly Dioscuri, within a frame of branches. — 1969