The technique of verre églomisé is similar to mosaic and Cosmati artworks in that gilded glass played an integral role in the composition; however, unlike the gold glass of the two aforementioned techniques, in verre églomisé the gilded panel was etched with imagery, sometimes floral motifs but in other cases figural compositions and even narrative scenes. To protect and seal the gold leaf imagery, the glass panel was backed with pigment. Thus, whereas the glass panels used in the two other techniques receive a consistent application of gold leaf, in verre églomisé gilding does not necessarily cover the entire panel of glass.
An early iteration of this technique dates back to ancient Greece, when Hellenistic glassmakers developed the method known as sandwich glass. In this process, rather than protecting gold leaf decoration with pigment, an art-ist sandwiched gold leaf designs between two sheets of glass. For example, in ancient Greek luxury works such as the Sandwich Gold-Glass Bowl from the third century BCE in the British Museum (inventory no. 1871,0518.2), elaborate foliage patterns of gold are sandwiched between two pieces of mostly transparent glass.29
Glass was more ubiquitous and affordable in Roman times, in large part due to the development of glass blowing, a factor that may have contributed to greater variety and experimentation.30 Roman artists frequently depicted more
Figure 3.2: Orcagna, Detail of Tabernacle showing gilded glass, 1359, Orsanmichele, Florence. Source: Francesco Bini via Wikimedia Commons (CC BY-SA 3.0).
complex figurative imagery and added a higher degree of etched details than Greek artists. Romans frequently used gold-glass roundels featuring pagan, Jewish, or Christian themes to decorate the bottoms of bowls, cups, and other vessels (Figure 3.3).31 Upon their owner’s death, the gold-glass medallions were detached from the functional objects they decorated and impressed into the cement wall of the deceased’s tomb in the catacombs. These examples are par-ticularly important because they would have been accessible to medieval view-ers when visiting the catacombs.
Figure 3.3: Byzantine Workshop, Bowl Base with Saints Peter and Paul Flanking a Column with the Christogram of Christ, late 4th century, The Metropolitan Museum of Art, New York, Rogers Fund, 1916 (16.174.3). Source: Public Domain, The Metropolitan Museum of Art (CC0).
Production of Roman gold glass peaked during the third and fourth centuries and then entered a period of sharp decline after the fifth century,32 as did glass production in the Latin West more generally.33 However, artists in Islamic terri-tories, especially near Syria and around Egypt, continued to produce sandwich gold glass as well as many other types of glass, as will be discussed in more detail in Chapter 4. Characteristic examples of Syrian sandwich gold glass include the fragmentary cup in the David Collection of Copenhagen (inventory no. 4/1987), a bottle in the British Museum (inventory no. 1978,1011.2), and a cup in the Corning Museum of Glass (inventory no. 64.1.32). The production of gold-glass objects in Islamic territories was brief and limited compared with Roman output, being primarily confined to the ninth and tenth centuries.34 Based on the rela-tively few extant examples and the short-lived nature of its production, Stefano Carboni suggests that Islamic gold glass was not commissioned by royal circles in a programmatic way but rather was an experimental response to the challenge of earlier Roman models.35
A resurgence of glass-making activities on the European continent occurred in the thirteenth century with the growing popularity of stained glass windows discussed in the last chapter. Gilded glass, too, experienced a revival, particularly in Italy with the technique of verre églomisé.36 The Latin West’s late-medieval revival of verre églomisé, a modified version of sandwich glass wherein the gold is backed with pigment rather than another sheet of glass, occurred in the later thirteenth cen-tury and was likely influenced by Roman examples.37 Though Greeks and Muslims both made significant contributions to the history of gilded glass, duecento and trecento artists, patrons, and viewers would have had limited access to examples of Greek and Islamic sandwich gold glass. In contrast, Roman examples would have been easily accessible in terms of number and location. Furthermore, the Roman gold-glass roundels (Figure 3.3), or at least those associated with early Christians, could have held profound religious associations for later medieval viewers.
Some scholars have argued that these roundels served as a type of headstone or identification label, while others have argued that they functioned as protective devices, guarding the tomb of the deceased.38 Although early Christians stopped using the catacombs as burial grounds after the fifth century, many Christians continued to visit the dead throughout the middle ages. Irina Taïssa Oryshkev-ich dispelled the previously held assumption that the catacombs went out of use during the later medieval and early Renaissance periods.39 She supported her claim with literary evidence such as the Mirabilia urbis Romae and hagiographic texts in addition to archeological evidence such as the construction of aboveground cemeteries and churches that were physically linked to the catacombs by tunnel.40
She found that, despite the fact that many of the relics were removed to churches inside the city walls in the eighth century, the catacombs continued to be a source of spiritual and artistic inspiration for people of the later Middle Ages. And in some cases, the subterranean rooms were even turned into shrines.41
Visitors to the catacombs increased greatly around the year 1300 when Pope Boniface celebrated the Jubilee by issuing a papal bull that awarded pilgrims to Rome a spiritual reward on par with that offered to crusaders. In addition to an association with the holy sites of Rome, the ancient gold glass medallions may have also carried the aura of a secondary relic, that is, an object sanctified by phys-ical contact with the remains of a holy figure. Not only did the gold-glass roundels press against the wall containing the remains of the deceased Christian martyrs, but while he or she was still living, the glass would have come into physical con-tact with the revered early Christian who had used it as a dish or vessel.
Evidence that a link between gilded glass and relics survived into early mod-ern times is provided by Cennino Cennini’s description of verre églomisé for his early modern treatise on artistic techniques, The Craftsman’s Handbook. Before outlining the instructions for the technique, he writes that verre églomisé is a
“process for working on glass, indescribably attractive, fine, and unusual, and this is a branch of great piety, for the embellishment of holy reliquaries.”42 The many extant reliquaries featuring verre églomisé indicate that fourteenth-century Italian artists in fact followed Cennini’s advice. As most of these reliquaries also incorporate another type of glass, namely transparent glass, they will be discussed separately in Chapter 6.
Gilded glass, with its long association with divine illumination, its striking visual qualities, and its important artistic precedents, seems to have been ideally suited for demarking a space where the heavenly and earthly worlds converged.
On the one hand, it is a solid, man-made, mundane material, and on the other, it produced a lighting effect that was elusive, immaterial, and supernatural. To investigate this premise further, the discussion that follows examines how specific artists, namely Nicola Pisano, Simone Martini, and Paolo di Giovanni Fei, each used the medium in a unique way, one that was suited to their specific context.43