The ancient monument is besieged each day by packs of brawny, sun-tanned touts who dress up in polished breast plates and plumed helmets and earn money by posing with tourists for photographs.
But many demand exorbitant sums, even from tourists who inadvertently catch them in their lens, and become abusive if their demands are not met.
Now, with the tourist high season approaching, and a £20 million restoration of the Colosseum underway, the city authorities have told the fake legionaires, centurions and gladiators to leave in order to restore "decorum" to the ancient arena.
But the crackdown has provoked fury from the warriors, who have vowed to put up a fight worthy of their forbears. The stand-off erupted into violence on Thursday, right on the doorstep of the Colosseum, as centurions in crimson tunics, armour and helmets clashed with police, who arrived at the ancient amphitheatre with eviction notices.
Punches were thrown and plastic swords waved around, in a mini-reconstruction of the kind of close-quarters combat for which the legions were renowned.