St. Telemachus

St. Telemachus (also known as Almachius) was stoned to death in the year A.D. 400 in Rome when he tried to stop a contest between gladiators in Rome.

A hermit who had come from the East, Telemachus entered the stadium and marched into the arena while the combatants were fighting. His objective was clear and practical: to expose and eradicate this unchristian, though popular, violence.

Apparently, he was successful. Moved by his witness, the emperor Honorius abolished gladiatorial combat.