The ancientCaiatia was already in the hands of theRomans in 306 BC, and since in the 3rd century BC it issuedcopper coins with aLatin legend it must have had thecivitas sine suffragio. In theSocial War it rebelled from Rome, and its territory was added to that of Capua bySulla. In the imperial period, however, it was once more amunicipium.[3]
Caiazzo was the seat of anti-royal rebellions at the times of theNeapolitan Republic, and also housed severalCarbonari. Despite this, Caiazzo was one of the few towns in the kingdom whose population sided againstGaribaldi'sexpedition which annexed southern Italy toPiedmont.
Caiazzo has remains of Cyclopean orpolygonal masonry walls, and under the Piazza del Mercato is a large Romancistern, which for centuries continued to provide a good water supply.[3]
