The city flourished during Roman times, as shown by the large mosaics at the patrician Villa Romana del Casale.

The main landmarks include a range of architectural styles: Outside the city is the ancient church of the Priorato di Sant'Andrea (1096), founded by Count Simon of Butera, a nephew of Roger I of Sicily.

Piazza Armerina holds an annual Palio dei Normanni, a re-enactment in costume of the entrance of the Norman Count Roger I to the city.

Piazza Armerina is one of the so-called "Lombard" communes of Sicily, as its dialect differs notably from that of the neighbouring region.

This is due to the destruction of the old Piazza by king William I of Sicily, and the subsequent repopulation by William II (according to other scholars, during the slightly later age of Frederick II) with colonists coming from northern Italy (then collectively called "Lombardy"), especially from Monferrato and Piacenza.