A remarkable building with a Renaissance facade. Inside there are many frescoes and valuable Baroque decorations.
With a protomedieval foundation, the church was denominated as a parish already in 818, declared a collegiate church in 1078 and cathedral in 1888. The current masonry is still mostly Romanic. During the 13th and 14th century, the vaulted ceiling was built and the church was expanded. The flying facade, erected in 1500/1517, is one of the Lombardian Renaissance’s masterpieces. The elements of the frontispiece, four supporting pillars, the middle cornice with a broken line and an entablature, are arranged in a highly harmonious way. The Chapel of Madonna delle Grazie was founded in 1494 and rebuilt in 1774 following the plans of architect Giambattista Casasopra. It is richly decorated with columns and a marble altar.
Its oldest frescoes can be admired on the inside facade wall, above the cross-vaulted ceiling from Gothic times: traces of a Universal Judgement, a prospective meander, the head of an Apostle and a small trace of an infernal abyss, date to the 14th Century. At the entrance of the choir, a majestic marble high altar with a superstructure and a small temple decorated with cherubs was built at the end of the 17th Century on a design by Andrea Biffi. In the last section of the south nave, an ancient octagonal baptismal font is inscribed and dated 1430.
