Conservation and Analyses of the Twelfth-Century Bronze Doors made by Oderisius of Benevento in Troia, Italy

In the context of the international GAPAMET project, a study was conducted on European metal doors from the eleventh-twelfth century CE, which were composed of various copper alloys. The aim of the project was to gain deeper insights into the manufacturing processes and subsequent modifications of these doors. Two of them, namely the doors from the cathedral of Troia, Italy, were made by Oderisius of Benevento at the beginning of the twelfth century. In this paper, we present, for the first time, chemical analyses of all the metal parts of the two doors and focus on the restoration of the main door on the cathedral’s façade in the 1990s conducted by one of the authors, which brought to light previously unnoticed remnants of further original panels that had been thought to be lost. Particular attention is paid to rearrangements and the addition of new panels over the course of time, and the usage of different leaded bronze alloys for the production of the various metal parts. Furthermore, we include in our study a discussion of the door handles from Sepino, also associated with Oderisius’ workshop, which were made of leaded bronze and quaternary Cu-Sn-Zn-Pb alloys.