Cathedral was built on the area where was originally ancient temple dedicated to St. Vigilio, Patron of city. Bishop Federico Vanga (1207-1218) decided to completely rebuild Cathedral to its foundations, entrusting the project to the workers led by Adamo d'Arogno, as evidenced by a plaque on the base of the apse. At the end of the thirteenth century north transept was decorated with a rose called "Wheel of Fortune" for its iconographic motif represented a topos of Medieval art. Between 1305 and 1307 Egidio Campione directed the work building the southern side of Cathedral and the bottom of the bell towers. In 1321 his son, Bonino Campione, created the rose window on the facade and added some Gothic elements. From 1545 to 1563 Cathedral housed Council of Trent. In 1682, by Giuseppe Alberti, it was built Chapel of Crucifix, a Baroque structure inserted in the forms almost totally Romanesque, while in 1739 it was realized the canopy of the high altar, inspired by Bernini.