The 12th-century copper alloy doors crafted by Barisanus of Trani are not just impressive artifacts; they also serve as prime examples of medieval craftsmanship and artistic expression. Recent studies utilizing advanced technology have provided new insights, enhancing our comprehension of their production techniques.
Located at the cathedrals of Ravello, Trani, and Monreale, these monumental doors have long been venerated for their artistic merit. The door from Ravello is dated to 1179, providing one of the limited temporal markers for Barisanus's outputs, as the construction of the Monreale door falls between 1174 and 1186, whereas the Trani door’s date remains undetermined.
An international project, underpinned by the Austrian Science Fund (FWF), recently documented these doors photogrammetrically and archaeometrically, developing digital twins for public access. These digital representations allow researchers to undertake precise measurements of the doors’ various metal components, bridging gaps left by traditional art historical analysis.
This groundbreaking study reveals substantial shrinkage across panels, with findings indicating up to 8.2% shrinkage, shedding light on the technical adaptations Barisanus utilized when creating these panels. Measurements showed the panels from Trani are consistently larger, with differences averaging around 1.4% compared to their counterparts at Monreale and Ravello.
One of the core revelations from this study was the identification of casting generations. By establishing shrinkage values—approximately 2.5% across different casting generations—researchers have proposed sequences of production, likely indicating the Trani doors preceded those at Monreale and Ravello.
For medieval artisans like Barisanus, casting was not merely about producing aesthetic objects. It entailed complex methodologies related to material properties, mold-making, and the incorporation of advanced techniques rarely seen before this period. The study found casting processes such as lost wax and sand casting were pivotal to Barisanus's techniques, though the exact interplay between these methods remains unclear.
Delving deep, the researchers noted, "the examination of the cast pieces and their production traces clearly shows...simplistic classification as being cast using the lost-wax process or the sand-casting method falls short of reflecting the realities of medieval foundry practices." This highlights the necessity of revisiting the manufacturing paradigms established through earlier analyses, as new findings draw attention to diverse techniques used beyond the traditional dichotomy.
Additional insights were gained from observing the decorative friezes and panels, with various motifs replicated with remarkable fidelity. The complexity of these motifs and ornamentations calls attention to potential auxiliary methods of replication, possibly involving prefabricated pieces or advanced stamping techniques. The Trani doors demonstrate significantly larger and more complex friezes compared to those of Ravello.
Such findings enrich the narrative surrounding not only Barisanus but also the technological advancements of 12th-century Italy, indicating potential cross-regional influences in metalwork and artistry. Notably, this study concludes with the observation, "a well established means of mechanical replication must have been known to the workshops...the panels are distinctly individual in the manner of the arrangement of...recurring motifs and friezes." This serves as compelling evidence of not just artistry but also of sophisticated workshop practices.
To summarize, the latest technological approaches to studying the doors of Barisanus provide transformative insights fundamental to our appreciation of medieval craftsmanship. Their production techniques, evidenced by both the revealed shrinkage data and the complexity of their designs, forge connections between historical artifacts and modern scientific inquiry, ensuring these monumental doors are rightly celebrated not only for their beauty but also for their technological significance.