Treasure from the rubbish pit: A pendant from the Middle Ages discovered during excavations in Mainz has now revealed a very special inner workings. Because the piece of jewelery made of gold-plated copper contains pieces of bone wrapped in silk - probably relics. This makes this 12th-century pendant, decorated with enameled images of Jesus, Mary and several saints, one of only four known phylacteries – mini reliquaries – of this type.
In October 2008, archaeologists led by Matthias Heinzel from the Leibniz Center for Archeology (LEIZA) made an unexpected find in the old town of Mainz: During excavations in a medieval rubbish pit, they came across a heavily corroded piece of jewelery made of gold-plated copper. The front and back of the pendant, shaped like a four-leaf clover, were decorated with colored enamel motifs. Closer investigation revealed that this pendant, which is around six centimeters in size, dates from the 12th century.
Is the pendant a reliquary?
The shape and thickness of the gold-plated pendant already suggested when it was found that something might be hidden inside. "But the object and above all the locking mechanism is badly damaged by the centuries of corrosion, and opening it would mean destroying it irrevocably," explains Heinzel. In 500 hours of work, the restorer first carefully freed the found object from the coarse corrosion deposits. This revealed that the front and back of the jewel are decorated with enamelled images of Jesus, the four evangelists, Mary and four female saints. The archaeologists also conclude from the design that the pendant was made around 800 years ago in a workshop in Hildesheim, Lower Saxony.
The shape of the piece of jewelry and the type of decoration also indicated that it could be a storage container for relics, a so-called phylactery. This term is derived from the Greek and means something like a means of preservation or protection. Such so-called phylacteries were worn on the body in the Middle Ages, usually around the neck, and contained small relics of a saint such as bones or pieces of clothing. According to the belief of the time, these relics should ensure their bearer the protection and assistance of the saint.
Neutron tomography reveals bits of bone inside
But did the Mainz pendant also contain such relics? Since the organic content of the object could not be seen on X-rays, the researchers used neutron beams to examine the medieval gem at a neutron source at the Technical University of Munich. Unlike X-rays, the neutrons can penetrate metals and make organic substances visible. The team was also able to determine which elements were contained in the object based on the neutron-triggered radiation emissions from the material.
“Neutron non-destructive testing was particularly useful because we couldn't just open the trailer and look inside,” explains Heinzel. Neutron tomography revealed that the pendant contained five packets of silk and linen, each containing some bone fragments. This confirms that the jewel is most likely a phylactery. "It is not possible to find out whether the bones are from saints and which saints the bone splinters can be assigned to," says Heinzel. “Most of the relics are accompanied by a strip of parchment with the name of the saint on it. In this case, unfortunately, we cannot see it."
One of only four phylacteries of this kind
The find from the medieval rubbish pit is one of only four known reliquaries of this type, the other three are kept in Rome, Boston and Halberstadt. During the restoration, Heinzel also discovered a cord fragment in the suspension eyelet, which turned out to be the remains of a silk cord. "This is the first evidence that such pendants may have been worn around the neck on a silk cord," says the researcher. "Thanks to the neutron tomography at the TUM, we were also able to measure the thread thickness and the thread spacing of the textiles inside." The find is in the possession of the Mainz State Archeology Directorate and can be viewed in the medieval exhibition “AUREA MAGONTIA – Mainz in the Middle Ages” at the Mainz State Museum until further notice.
Source: Technical University of Munich; Specialist article: Proceedings of the interim meeting of the ICOM-CC metals working group 184-191 (2022)