The building works began in 1122 on the remains of the pre-existing cathedral of S.Giustina, to be concluded in 1233. Its façade is characterized by two buttresses in sandstone in the upper part and in pink marble below. 

The three portals are each surmounted by a prothyrum. These are supported by masterpieces of Romanesque art, sculptures produced by Piacenza workshops inspired by the models of Wiligelmo and Nicolò. 

The tower and dome date back to the 14th century. Inside, Baroque art is exemplified in the frescoes by Carracci and Procaccini in the presbytery, and Guercino and Morazzone in the dome. The “Lo sposalizio di Santa Caterina” (Saint Catherine’s wedding) by Robert de Longe is also interesting. 

Also notice the panels of paratici which are testimony to the participation of local artisans to the building of the cathedral. The baptistery pool dates back to the pre-Christian era and attests the ancient origins of the Duomo. 

Popular devotion at the beginning of the 17th century dedicated particular attention to Madonna del Popolo with the chapel bearing the same name. On the opposite side there is the tomb of Beato Giovanni Battista Scalabrini. 

In the crypt there are the relics of S. Giustina. Also very important is the capitular archive. The bell tower has a square plan and is built in cotto bricks, standing tall next to Duomo reaching 67 metres of height. 

On the top of its cone roof the master mason Pietro Vago in 1341 installed a revolving angel in golden copper. The statue is one of the symbols of the city, nicknamed by Piacenza people "L'Angil dal Dom". 

The iron cage located on the outside wall of the bell tower was put there in 1495 upon orders of Lodovico il Moro, serving as warning to wrongdoers.