The trade has been tolerated for years, but that was before about 20 of the practitioners began assaulting and intimidating their competitors to take over lucrative tourist spots such as the Colosseum, the Forum and the Vatican, officials and police said Friday.
So police decided to intervene disguised as gladiators, garbage collectors and tourists, but their operation at the ancient arena and the nearby Piazza Venezia wasn't easy.
On Wednesday, police impersonating gladiators were attacked when they told competitors to leave the scene, but police dressed as garbage collectors and tourists came to their rescue.
The Rome newspaper Il Messaggero said one suspect demanded the money a woman tourist had paid for a photo of herself with a gladiator, but it turned out the pair in the photograph were both undercover officers.
Italian media carried photos or TV footage showing a handcuffed gladiator being taken away and a policeman pretending to be a tourist wrapping an arm around a gladiator's neck.
None of the civilian gladiators were arrested while the probe continues.
Police estimate that about 30 such tradesmen are scattered around Rome's top tourist attractions on a normal day, the majority around the Colosseum, where in the city's ancient glory days real gladiators engaged in combat to the thrill of the masses.
In future, such crackdowns may be easier.
Antonio Gazzellone, the mayor's point man for tourism, said there are no regulations controlling the activity of such gladiators but that parliament is considering a law that would allow police to quickly intervene in case of aggressive behavior by the impersonators.