Final answer:
The gesture traditionally associated with the emperor condemning a gladiator to die after an appeal was 'thumb down', though interpretations vary. Emperors could influence such decisions, and laws existed to regulate the participation of certain classes in gladiatorial combat.
Step-by-step explanation:
In ancient Roman gladiatorial combats, when an appeal was made for the life of a defeated gladiator, the emperor had the power to decide the fighter's fate. The gesture for condemning a gladiator to death was traditionally believed to be “thumb down”, though some historical interpretations suggest various gestures could be used.
The emperor's decision was heavily influenced by the reactions of the spectators, who could sway the outcome by either cheering for mercy or demanding the fighter's death. Emperors like Commodus, who was known for his unusual behaviour, also played a role as trendsetters in such events despite societal norms.
Additionally, laws passed to discourage certain classes from participating in gladiatorial games, such as the prohibition against senators enacted by Tiberius, indicate the complex social dynamics at play surrounding these spectacles.