A team of researchers has used cutting-edge scientific tools to help solve a long-standing mystery in medieval art history: the chronological order of the monumental bronze doors created by the 12th-century artisan Barisanus of Trani.
Long admired for their intricate reliefs and craftsmanship, the doors of the cathedrals in Trani, Ravello, and Monreale are some of the finest surviving examples of medieval bronze work. But until now, scholars have debated which of these masterpieces came first. In a new open-access study published today in PLOS ONE, researchers combined high-resolution 3D imaging, chemical analysis, and art historical research to investigate how the doors were made—and when.
“The measurements of the selected panels present on all three doors, which provide information on model and metal shrinkage, confirmed that the Trani door is the oldest of the three surviving Barisanus doors,” the team writes.
A Medieval Bronze Workshop Comes to Light
The Bronze door at Trani – photo by Holger Uwe Schmitt / Wikimedia Commons
Barisanus of Trani was one of the most productive bronze-casters of the High Middle Ages. Though few records of his life survive, his name appears on the doors of Trani and Monreale, and stylistic similarities link him to the Ravello door as well.
Like earlier Byzantine examples, these Italian bronze doors consist of flat panels affixed to wooden supports, but Barisanus’s work is distinctive for its engraved flat reliefs and its iconographic program—dominated by saints, the Maiestas Domini, and scenes such as the Harrowing of Hell.
The question of which door came first has long hinged on art-historical interpretation. Scholars often assumed Ravello was oldest due to its relatively modest ornamentation, with Monreale considered the most elaborate and thus latest. But this new study challenges that developmental narrative.
Shrinking Saints and Digital Twins
Bronze door in the cathedral of Ravello. Photo by Rigorius / Wikimedia Commons
Using photogrammetry, the researchers created precise 3D models of the door panels, allowing for minute comparisons between repeated motifs—like Saint George or John the Baptist—across the three sets of doors.
When metal is cast, it shrinks as it cools. If one door’s panel was a copy of another, it should be slightly smaller. Measuring these differences gave researchers a new way to establish sequence.
The results? The panels from Trani were consistently the largest—suggesting they were the originals from which the others were modeled. Ravello came next in some cases, but in others, Monreale was second—pointing to concurrent or overlapping production, not a simple linear progression.
What the Metals Revealed
The doors at Monreale – Photo by Holger Uwe Schmitt
Chemical analysis (via portable X-ray fluorescence and principal component analysis) confirmed further differences. All three doors were made of leaded bronze, but each used slightly different metal compositions.
Most striking was the Monreale door, which contained high levels of antimony—up to 7%—a rare feature that may reflect local ore sources in Sicily’s Peloritani Mountains.
This suggests the doors were likely cast near their respective cathedrals using locally sourced materials, and that the wax models—not the finished molds—were what traveled between locations.
Rewriting the Workshop’s Legacy
The study not only helps date the surviving doors but also offers a more nuanced picture of how Barisanus’s workshop operated. Rather than a fixed atelier producing objects in sequence, it appears the workshop reused models flexibly, responding to patron needs and casting doors on site. And thanks to digital imaging and metallurgical science, art historians now have a firmer foundation to study one of the medieval world’s most important metalworking traditions.
“Distinguishing between originals and casts has become significantly more feasible,” the authors write, “and since these observations are grounded in quantifiable data, they can bolster hypotheses that previously relied solely on stylistic considerations.”
The article, “The 12th century bronze doors of Barisanus of Trani in Trani, Ravello and Monreale,” by Marianne Mödlinger, Bastian Asmus, Martin Fera, Judith Utz and Giorgia Ghiara, is published in PLOS ONE. Click here to read it.
The research is carried out by GAPAMET (Gates to Paradise: Creating metal doors for 11th-12th century churches) project, which is headed up by Marianne Mödlinger of the University of Genoa. Earlier this month, members of this team also published the article “Deconstructing Barisanus’ medieval casting technology based on digital twins” in Scientific Reports.
Glad to see another outcome from the GAPAMET-project by Marianne Mödlinger dealing with medieval bronze doors.
This time we investigated with Bastian Asmus the casting technology of Barisanus with high resolution orthomosaics and DSMs. Read the publication here:
Top Image: The four doors from Barisanus of Trani. Relief visualization of digital surface models (DSMs). Image credit: Mödlinger et al., 2025, PLOS One, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)
A team of researchers has used cutting-edge scientific tools to help solve a long-standing mystery in medieval art history: the chronological order of the monumental bronze doors created by the 12th-century artisan Barisanus of Trani.
Long admired for their intricate reliefs and craftsmanship, the doors of the cathedrals in Trani, Ravello, and Monreale are some of the finest surviving examples of medieval bronze work. But until now, scholars have debated which of these masterpieces came first. In a new open-access study published today in PLOS ONE, researchers combined high-resolution 3D imaging, chemical analysis, and art historical research to investigate how the doors were made—and when.
“The measurements of the selected panels present on all three doors, which provide information on model and metal shrinkage, confirmed that the Trani door is the oldest of the three surviving Barisanus doors,” the team writes.
A Medieval Bronze Workshop Comes to Light
Barisanus of Trani was one of the most productive bronze-casters of the High Middle Ages. Though few records of his life survive, his name appears on the doors of Trani and Monreale, and stylistic similarities link him to the Ravello door as well.
Like earlier Byzantine examples, these Italian bronze doors consist of flat panels affixed to wooden supports, but Barisanus’s work is distinctive for its engraved flat reliefs and its iconographic program—dominated by saints, the Maiestas Domini, and scenes such as the Harrowing of Hell.
The question of which door came first has long hinged on art-historical interpretation. Scholars often assumed Ravello was oldest due to its relatively modest ornamentation, with Monreale considered the most elaborate and thus latest. But this new study challenges that developmental narrative.
Shrinking Saints and Digital Twins
Using photogrammetry, the researchers created precise 3D models of the door panels, allowing for minute comparisons between repeated motifs—like Saint George or John the Baptist—across the three sets of doors.
When metal is cast, it shrinks as it cools. If one door’s panel was a copy of another, it should be slightly smaller. Measuring these differences gave researchers a new way to establish sequence.
The results? The panels from Trani were consistently the largest—suggesting they were the originals from which the others were modeled. Ravello came next in some cases, but in others, Monreale was second—pointing to concurrent or overlapping production, not a simple linear progression.
What the Metals Revealed
Chemical analysis (via portable X-ray fluorescence and principal component analysis) confirmed further differences. All three doors were made of leaded bronze, but each used slightly different metal compositions.
Most striking was the Monreale door, which contained high levels of antimony—up to 7%—a rare feature that may reflect local ore sources in Sicily’s Peloritani Mountains.
This suggests the doors were likely cast near their respective cathedrals using locally sourced materials, and that the wax models—not the finished molds—were what traveled between locations.
Rewriting the Workshop’s Legacy
The study not only helps date the surviving doors but also offers a more nuanced picture of how Barisanus’s workshop operated. Rather than a fixed atelier producing objects in sequence, it appears the workshop reused models flexibly, responding to patron needs and casting doors on site. And thanks to digital imaging and metallurgical science, art historians now have a firmer foundation to study one of the medieval world’s most important metalworking traditions.
“Distinguishing between originals and casts has become significantly more feasible,” the authors write, “and since these observations are grounded in quantifiable data, they can bolster hypotheses that previously relied solely on stylistic considerations.”
The article, “The 12th century bronze doors of Barisanus of Trani in Trani, Ravello and Monreale,” by Marianne Mödlinger, Bastian Asmus, Martin Fera, Judith Utz and Giorgia Ghiara, is published in PLOS ONE. Click here to read it.
The research is carried out by GAPAMET (Gates to Paradise: Creating metal doors for 11th-12th century churches) project, which is headed up by Marianne Mödlinger of the University of Genoa. Earlier this month, members of this team also published the article “Deconstructing Barisanus’ medieval casting technology based on digital twins” in Scientific Reports.
Top Image: The four doors from Barisanus of Trani. Relief visualization of digital surface models (DSMs). Image credit: Mödlinger et al., 2025, PLOS One, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)
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