The Chapel of Teodolinda is located in the Cathedral of Monza in the northern arm of the transept. The chapel holds the famous iron crown, which is kept in a special altar, built by Luca Beltrami in 1895 – 96
The Crown or rather diadem is composed of six plates made of gold -alloy of app. 80% purity. These plaques are linked by vertical hinges. It measures 15 cm in diameter and has a height of 5.5 cm. It weighs 535 gr. It is adorned with 26 golden rosettes, 22 gems of various collars and 24 laminae of floral cloisonné enamel. The buds are red garnets, purple amethysts and blue corundum. Other decorations are made of glass paste. Each plate of ornamental components have been clamped on externally at the corners. These plates or laminae are made of a fine, thin gold plate covered with glass and ornamental decorations. Inside is fitted what used to be believed was the actual “iron-crown” (see below).
Art Historical Study
Recent art historical studies have found that the crown is the result of a series of re-workings carried out between AD 300 – 900. According to these, it is now believed that part of the crown was originally made by Eastern goldsmiths, perhaps even at the time of Constantine and fitted to his helmet. This used to hang in Hagia Sophia until 1204 together with his bridle. Both these artifacts were made of the nails used to crucify Christ, which legend told been found by St. Helen. According to St. Ambrose this diadem was taken from the helmet and worn by Theodosius († AD 395). After his death in Milan it seems to have been kept there, from where it passed into the hands of first the Ostrogoths, later the Lombards and finally the Carolingians. During this period it seems to have been continuously reconstructed and repaired.
Especially Charlemagne is believed to have been part of a major reconstruction as the golden diadem (inside which the “iron” ring is mounted) may have come from the same workshop as that, which made the golden altar in St. Ambrose in Milan. This is also characteristic of a burse reliquary, which is also kept in the treasury of the Monza Cathedral.
Later – perhaps in the 12th century – it appears the crown sported an iron ring on top of the crown. However around 1300 it was called “small”. One hypothesis is that the iron-ring and two plaques were stolen in the 13th century, leaving us with what is now the remains of what is basically an artefact too tiny to fit to the head of any emperor.
In the Early Middle Ages it was consistently used to crown the Holy-Roman Emperors as king of Italy in Milan before they were crowned emperor in Rome.
A number of scholars have questioned the identification with the diadem, Ambrosius mentioned in his panegyric of Theodosius with that of the Iron Crown presently kept in the chapel in Monza.
However, in 1997 a series of scientific investigations into the crown were published by Milazzo and Cicardi. Basically these showed that the metal composition of the gold alloy used to form the body of the crown was of a single uniform composition. However, a study of the laminae (the attached plates) had a distinctly higher component of gold and must have been made from another source of alloy. Apart from this the scientists succeeded in extracting small amounts of fusion earth mixed with vax from behind two gems and one of the small plaques. Calibrated calendar dates revealed were AD 699 -776 and AD 445 – 565 respectively.
Inside the crown there is supposedly a ring of “iron”, which according to “ancient tradition” was made out of one of the nails used in the crucifixion of Christ. According to this tradition the nail was one of those found by St. Helen in 326, which she later had inserted in a diadem, which she gifted to her son, the emperor Constantine.
However the scientists also discovered that this iron-ring was in fact made of pure silver; probably it was fitted around 1345 to keep the smaller crown together. In fact, it was not until the 16th century the elaborate myth was created, that this inner ring was in fact made out of one of the “iron” nails, which a miracle had kept from rusting.
In 1995 – 98 an interdisciplinary group of scholars, historians and scientists published a state of the art presentation of this famous medieval treasure.
The crown is kept in the Chapel of Teodolinda, which has been recently restored.
X-Ray Fluorescence Characterization of the Corona Ferrea
BY M. Milazzo and C. Cicardi
In: Archaeometry 1998, Vol. 40, No. 2, pp. 351 – 360
La Corona Ferrea nell’Europa degli Imperi Vol 1 – 4
By Augusto Calderara and Graziella Buccellati et al. (eds)
Series: Società di Studi Monzesi.
Mondadori 1995 – 98
La corona ferrea. La storia del più antico e celebre simbolo del potere in Europa
By Valeriana Maspero
Vittone Editore, Monza 2003.