A gladiator was a professional athlete and combatant in ancient Rome. Gladiators contested with each other or with wild animals. At first they were drawn from the slave and prisoner classes exclusively; however, successful gladiators came to be held in such high esteem (rather like today's sorting superstars) that men started to make a profession of athletics and gladiatorial training schools were established.
When a gladiator was vanquished without being killed in combat, it was left with the spectators to decide his fate, death being voted by holding the hands out and the thumb turned inward, and life by putting forth the hands with the thumb extended. Gladiatorial shows were the chief public displays in Rome from the third to the fourth centuries AD.