Castello dell'Imperatore

Prato’s Castello dell’Imperatore is the only surviving example of Swabian architecture in central-northern Italy. Built for Emperor Frederick II between 1237 and 1248, it combines a square plan and corner towers with imperial lions carved in green serpentine and pale alberese stone.

Why it matters

The castle was built by the emperor’s architect Riccardo da Lentini to guard the route between the Holy Roman Empire and southern Italy and Sicily. Frederick II never came to Prato; his Tuscan vicar resided in the fortress. Its later history reflects the changing power of the city: in the fourteenth century, the Florentine government turned it into a military garrison and prison and connected it to the city walls through the covered Cassero passage.

What to notice

The fortress has a square plan reinforced by square towers. Its Ghibelline swallowtail merlons were restored in 1933. At the entrance, carved Swabian lions in serpentine and alberese mark the imperial association. A stairway leads to the wall walk, which runs along three sides of the perimeter. The towers also contain works by contemporary artist Salvatore Cipolla, whose pieces refer to Frederick II’s era.

Context and history

Frederick II’s castle remained part of Prato’s military defenses under Florentine rule and later served as a garrison and prison. Its wall walk and corner towers preserve the fortress’s defensive form, while the Cassero passage connected it to the city’s walls. The structure now also hosts cultural events, including summer concerts and open-air cinema.