Terracotta figurine of 2 gladiators
Roman, 1st-2nd century AD
Early representations of gladiatorial combat show both men dressed and armed in the same way. However, there was a change in the late republican period (1st century BC) when a number of different categories evolved, with different armour and weapons. By the Imperial period (1st-4th century AD), we have evidence of around a dozen clearly distinct armatura, or gladiatorial categories. The variety of armour and weapons meant that each had different strengths and weaknesses, making the combat more interesting.
The distinctive small shields of this pair of gladiators show that the duel is between two heavily-armed combatants, a hoplomachus with circular shield and a thraex, with small rectangular shield. The thraex, armed in the Thracian style, and the hoplomachus, with his Greek equipment, were usually pitted against the murmillo, armed like a legionary, mimicking the opposition between Roman soldiers and their various non-Italian enemies.
E. Köhne and C. Ewigleben (eds.), Gladiators and Caesars: the po (London, The British Museum Press, 2000)