Ancient early-Christian basilica, built between 350 and 375 by San Vittore, first bishop of Piacenza. Nearly destroyed during barbaric invasions, it was built again in 1014 and modified several times. In 1450 the left transept was extended with a hall, called Porta del Paradiso, made of a high lancet arch surmounted by a rose window and decorated with spires. Inside Paradiso a memeorial tablet recalls the meeting, occurred here in 1183, between the Lombard League ambassadors and the emperor Barbarossa (Frederick the Red beard), to discuss the preliminaries of the Peace of Konstanz. Inside, there are several frescoes by Camillo Gavasetti (1622). In the museum, we find polyptychs, finely drawn antiphonaries dating back to the end of the 15th century,silvers, goblets, reliquaries and a precious manuscipt by Lotario king of Lorraine dating back to 840.