The Corona Ferrea (Iron Crown) is held in the chapel of Theodolinda in the Duomo in Monza. This was made during the early Middle Ages (probably 5th c.) using, the tradition is, a nail used in the True Cross.
The crown was used in the coronation of the kings of Italy from the Middle Ages: Charlemagne, Otto I, Berengario I, Corrado II, Frederick Barbarossa, Henry IV, Charles IV, Napoleon and Ferdinand Hapsburg all made use of it.
Made from hinged segments of gold, it is decorated completely with enamels and precious stones and with floral reliefs locked by an iron flower, which tradition says was formed using a nail from Christ's Cross.
From the cloister, you can enter the Museum of the Treasure in which splendid objects and curios from the 5th and 6th centuries are kept. There is also oil taken from the tombs of the Martyrs, the 16 tin ampoules from the 6th century. which came from Palestine and are historiated with episodes of the life of the Evangelists. Then there is the gold cover of Theodolinda's prayer book, and the cross of Adaloaldo, Theodolinda's son, which is a true masterpiece of Byzantine art.
These are just some of the wonderful works of art in this small museum.
Milan