Begun at the beginning of 1480, it was consecrated in 1499 and completed in 1568. In the 17th century the church underwent some modifications: the choir and presbytery were raised, the side chapels were opened, some houses added and the belfry was built .In 1800 the collegiate church underwent other interventions, such as the reconstruction of the façade according to a design by Guglielmetti. The old renaissance façade, with two superimposed orders , is represented in a drawing dating back to 1766. In 1895 two funerary monuments by Pallavicino were transported into the cathedral.