The Cathedral Treasury, owned by the Metropolitan Chapter and originally kept in the vestry cupboards, was exhibited in 1962 in the Cathedral crypt. Since 2013 it has been housed in the Museum and consists of liturgical and religious objects used in Milan Cathedral from the 5th to the 17th century. Archbishop Gotofredo’s holy water bucket, called situla, dates back to the 8th century A.D. The Evangeliary Cover called “Diptych of the five parts” made of ivory and silver, commissioned by Archbishop Gotofredo at the end of the 5th century, is a fine example of Ottonian art. The Cross of Aribert, consisting of two half shells, in ivory, gilded silver, glass paste, stones and pearls, from the church of St. Dionysius in Milan, which no longer exists, is a very precious fragment of the remaining decoration of the tomb of Ariberto di Intimiano, bishop of Milan in the 11th century. Together with the tomb cover, consisting entirely of gold and silver with precious enamels, the Crucifix represents a further source of information testifying to the importance of Bishop Aribert, a prominent figure in the Church and Municipality of Milan.

One of the most interesting exhibits is the Madonna known as the “Madonna of the Idea”, a double-sided painting on wood, dating from the beginning of the 15th century by Michelino da Besozzo: on the front is the Madonna enthroned, on the back the Presentation in the Temple.