In the Christian Museum and Treasure of the Duomo are kept some really unique masterpieces that testify the excellent level achieved by the Byzantine, Longobard and Carolingian culture during the early middle Ages. Magnificent examples are the Ratchis Altar and the Baptistery of Callisto.  Recently the Museum has been restored and enlarged and now hosts almost all of the  so-called Treasure of the Chapter, mainly silverware, priceless jewels finely manufactured long back in the years.

In the halls located upstairs are displayed many important paintings, the major of these ascribed to the famous masters of arts Pordenone and Veronese. The last hall contains the sumptuous and old-dated liturgical vestments belonging to the Chapter. The so-called Chasuble of the Barbarian is made out of an antique Ottoman cloth, presumably manufactured in the 13^th century: museums of all over the world request the possibility to exhibit it so to testify the relationships at those times flourishing  between the Republic of Venice and the Islamic world, eastwards.

The Museum – with the purpose of installing a user friendly layout and also to enhance the value of the objects displayed – has recently accomplished a project that consents to have a polychrome view of the Altar of Ratchis; it shows how it could possibly appear to the a Longobard since the coloured lights are directly projected over the artefact, in absolute compliance with a historical and philological thread, validated by a strictly accurate scientific and historical research itinerary.