Gladiators were athletes who in ancient Rome fought with a small sword (the gladius, hence their name) for the amusement of crowds.
The gladiator shows first spread among private individuals, meeting with increasing success, and in 105 BC became public shows much appreciated by the masses during the Roman Empire.
Initially, gladiators were prisoners of war or those condemned to common offences, but with the growing success of this practice it became more and more common to have real schools to train them.