A rediscovered Cosmatesque plaque at the Church of the Holy Sepulchre (© Israel Antiquities Authority)

One of the largest medieval altars on record was recently rediscovered at the Church of the Holy Sepulchre in Jerusalem — a holy Christian site where Jesus was crucified and believed to have been buried. Beyond its distinguishing size, larger than any other of its kind dating from medieval Rome, the altar plaque is one of only two instances of Cosmatesque ornamentation that survives outside Italy. (The other is at Westminster Abbey, on the floors leading up to the High Altar and on the tomb of Saint Edward the Confessor, as well as several royal tombs.)

The “Cosmatesque” designation will be foreign to most — even medieval art historians — Ilya Berkovich, one half of the duo that made this discovery, told Hyperallergic in an interview.

Suffering a shortage of marble in medieval Rome, a group of families now referred to as the Cosmati — taking their name from the Cosma, the principal family among the craftsmen — developed a technique for fashioning inlaid marble and glass that hinged on repurposing fragments of marble taken from classical ruins and other sources.

Confronted with many small pieces of marble, sometimes just centimeters in length, in various random shapes, they came up with an elegant design solution to optimize the material that was available to them: the fragmentation of space.

Inside the marble patterns, Berkovich said, were “figures inscribed within figures: a triangle within a triangle within a triangle, a hexagon within a hexagon within a hexagon, a star within a star within a star, and of course, combinations of different figures.”

A recurring motif in their work is the loopy quincunx, which can be found underfoot at about a dozen churches in Rome.

A close-up image of a quincunx detail (© Israel Antiquities Authority)

The Cosmati were active for two centuries from roughly 1100 to 1300, and their designs drew from a range of influences including classical, Byzantine, and early Islamic art, mainly decorating floors of churches. Enjoying papal patronage, their influence was significant: In Rome, they decorated about 80 churches, and 50 more outside Rome but within the Papal States.

“The Church of the Holy Sepulchre is probably the most important church in Christianity,” Berkovich told Hyperallergic. “With the benefit of hindsight, perhaps it is not so surprising that we find a second example of [Cosmatesque art there].”

The loss of Cosmatesque art to the selectively destructive force of time also explains why it is relatively unknown today: Only about 20% of it is thought to have survived into the 21st century. 

Berkovich, a military historian and research associate at the Austrian Academy of Sciences, jointly made this finding with Amit Re’em, senior archaeologist at the Israel Antiquities Authority. Berkovich had built up a database of over 600 firsthand accounts of Crusader-period pilgrims and tourists visiting Jerusalem, some of them describing their trips to the Church of the Holy Sepulchre.

When Catholic, Greek Orthodox, and Armenian Apostolic churches came together in 2016 to restore the Edicule, the shrine that surrounds what is believed to be Jesus’s tomb, workers turned over every piece of marble and stone lying around in the church for the sake of due diligence, discovering the altarpiece, which had been neglected for decades and graffitied over on its backside. 

The unassuming back of the Cosmatesque plaque has been graffitied over by modern visitors. (© Israel Antiquities Authority)

What makes this find particularly exciting to the scholars is that they can date the consecration of the altar to the day: July 15, 1149. In his writings on his travels, German priest and pilgrim John of Würzburg was the first to describe the Church of the Holy Sepulchre after a major Crusader reconstruction that tripled the size of the church, integrating the prior Byzantine building into the new building. He quoted an inscription that read that on July 15, 1149 — the 50th anniversary of the conclusion of the Siege of Jerusalem — four new altars were dedicated in the church. Although the inscription has gradually deteriorated over the centuries and has now been entirely lost, the pilgrim’s account helps historians securely place a date on the Cosmatesque work.

By the 17th century, a Catholic official working in the Franciscan monastery in Jerusalem commented that although the high altar had previously been decorated with beautiful marble and other elements, more and more of them were falling out.

Despite how precious the altar must have been, few people were ever able to lay eyes upon it. Until the early 19th century, visitors were admitted in the evening, navigating the ambulatory by candlelight. Most of them would have walked around the sanctuary, bypassing the altar, their attention singularly trained on Jesus’s grave. The altar also resides in the section of the church that is Greek Orthodox-owned, so those who visited were primarily clergymen.

“The direct view into the old Crusader sanctuary was blocked by a beautiful, gilded screen with paintings and icons, so you couldn’t see the altar,” Berkovich said.

Berkovich and Re’em will be publishing their research later this year, and hope that Cosmatesque art specialists might be able to identify the artist who designed this altarpiece.

Jasmine Liu is a former staff writer for Hyperallergic. Originally from the San Francisco Bay Area, she studied anthropology and mathematics at Stanford University.