To better understand the relic windows in the aforementioned reliquaries, it is necessary to investigate some of the complex factors that contributed to the West’s growing interest in putting their relics on display.26 As Chapter 4 describes, at the same time as glass production was escalating, early Christian pilgrims making the journey to the loca sancta brought back holy souvenirs made from glass, or recorded this practice in their pilgrimage accounts. Another potential source of inspiration may have been Fatimid crystal pilgrim flasks, which were typically integrated into a larger reliquary ensemble as discussed in the last chapter. A third
important influence came from the east in the form of Byzantine reliquaries.27 Although Byzantine reliquaries do not generally feature an extensive use of glass, they did offer visual access to the relics and thus may have contributed to the desire to see the relics. The Limburg True Cross Reliquary (Staurotheke) in the Diöz-esanmuseum, Limburg for instance, allowed the privileged viewer to slide open the lid to reveal the sacred wood of the true cross and then open the smaller doors for access to numerous secondary relics. Another method of display in the Byzan-tine tradition was to leave the relic largely unadorned, as seen in the Skull Relic of Saint James the Younger from before 1204 and now in the Domschatzverwaltung, Halberstadt. When removed from its case, the viewer had direct visual access to the skull, which has been embellished and decorated but left mostly visible. Both of these reliquaries entered Europe after the Sack of Constantinople in 1204, making them particularly informative examples for an analysis of the Byzantine influence on western reliquaries from the trecento.
The relationship between the Byzantine Empire and the Latin West is a com-plex one that reaches as far back as antiquity, when their cultural heritages were united within the Roman Empire. In the centuries following the fall of Rome, the Byzantine Empire flourished while the western territories experienced a period of political instability beginning in the fifth century and lasting until Charlemagne.
Theological differences came to fruition in 1054 with the East–West schism but relations were maintained for various reasons such as a mutual interest in the Holy Land, the shared value of Christian relics, a desire to keep the Biblical holy sites in the possession of Christian forces, and a common enemy in Islam.
As the Byzantine emperor possessed many of the most important relics of the Passion of Christ, he was the gatekeeper to the Latin West’s access prior to the 1204 Sack of Constantinople. The emperor capitalized on this powerful position by sending western dignitaries relics as diplomatic gifts, determining whether a visitor to Constantinople was granted access to them, and presenting European hosts with relics when he traveled abroad.28 However, the situation changed dra-matically after 1204 when what began as an Italian-led attempt to wrest the holy city of Jerusalem from the Muslims ended with the looting of the Imperial Trea-sury of the Eastern Christians. The wide-ranging benefits gained from the 1204 Sack of Constantinople included booty such as the famous bronze horses that were to grace the top of Saint Mark’s, an impressive amount of tesserae, and numer-ous glass and crystal luxury objects.29 Many important reliquaries were part of this loot and, therefore, were removed from Byzantium and brought to the Latin West. Because of their revered status, when these objects entered western collec-tions, they would have been viewed as highly valued and thus very influential.
A particularly informative moment of artistic exchange is revealed when the aforementioned Limburg True Cross Reliquary, which entered the west as booty from the Sack of 1204, is compared with the Cross Reliquary at Trier from the first half of the thirteenth century.30 It is immediately evident that the reliquary at Trier closely emulated the overall composition of the reliquary at Limburg, borrowing the scale and central placement of the cross as well as the checkerboard setting of various small panels containing many more relic fragments. When com-paring the two, however, it is important to note their differences. In the Byzantine example, the smaller relics are accessed by opening the doors while the reliquary at Trier displays the relics behind pieces of transparent crystal. In the Byzantine work, the relics are either enclosed behind the small golden doors or exposed, while in the work from Trier, the relics are simultaneously contained and revealed in accordance with church regulations.
The Cross Reliquary at Trier demonstrates how a European artist might have fused Byzantine influence with western artistic traditions and religious customs.
The use of the transparent glass for relic windows was not yet widespread in the thirteenth century but the desire to view relics through a translucent or transpar-ent material such as rock crystal was already well established. For example, The End of a Reliquary Shrine with the Triumphant Christ in the Walters Art Museum (inventory no. 57.519) from the Mosan region31 features thin sheets of translu-cent horn in a similar manner, while The Reliquary of Saint Francis in the Louvre (inventory no. OA 4083) uses rock crystal.
Another association that may have inspired the increasing use of glass in rel-iquaries was this medium’s ancient associations with venerated remains. There were many glass vessels to be found throughout the Roman catacombs, which is not surprising considering that Ancient Rome had one of the most prolific glass industries. The vitreous medium was used for everything from dishware to win-dows.32 Glass was also used to make large storage vessels, some of which were used as funerary urns. These jars came in a variety of formats, some with handles, some without handles.33 They are made of thick blue-green glass, which is the naturally occurring color of this glass; however, some colored glass jars have been found.
Oftentimes they have lids that served as funnels through which one could pour an offering of liquid. A second type of ancient Roman glass associated with burial sites is the sandwich gold glass, called this because gold leaf designs are sand-wiched between two sheets of transparent glass. As discussed in Chapter 3, gold glass roundels featuring pagan, Jewish, and Christian motifs typically decorated the base of a drinking vessel or bowl and after their owner’s death, these functional objects were strategically broken to free the gold glass roundels and impressed into the cement wall of the deceased’s tomb in the catacombs (Figure 3.3).34
In addition to their association with the holy sites of Rome, the ancient gold glass roundels may have also carried the aura of a secondary relic, that is, an object sanctified by physical contact with the body of a holy figure. Not only did the glass roundels press against the wall containing the remains of the deceased martyrs but, also, while he or she was still living, the glass object would have come into physical contact with the saint when the bowl or plate used. Considering this, it is not difficult to imagine that an encounter with these gold-glass roundels could have held spiritual importance for the medieval Christian and may have influenced their reception of verre églomisé in Christian reliquaries.
Both the gold glass roundels and the glass funerary urns were likely seen by many medieval and Renaissance pilgrims. The Roman catacombs were popular sites for Christians searching for sacred tombs such as that of Saint Peter, espe-cially when pilgrimages to Rome increased during the fourteenth century. Seen as both a response to already occurring pilgrimages and an impetus for more in the future, Pope Boniface’s papal bull, the Antiquorum habet fida relatio, codified a generous indulgence policy for the Roman Jubilee in 1300 that awarded pilgrims to Rome a spiritual reward similar to that offered to crusaders.35 Inspired by the promise of salvation, early modern Christians traveled to Rome to pray at, among other sacred sites, the burial grounds of the venerated Early Christian martyrs.
Thus, by the time the trecento reliquaries with relic windows were being made, there may have already been strong connections between Christian relics and the vitreous medium.