A major aim of the Museum's acquisition policy is the procurement of objects of the highest artistic merit, while building strength and continuity in the collections. A late twelfth-century, double-armed reliquary cross believed to be from Limoges (Figure 1), acquired by the Museum earlier this year, satisfies all of these criteria. Curators in the Department of Medieval Art and The Cloisters first learned of the cross in 1993, but possible import restrictions and the asking price at that time placed it out of reach. Also of great concern were doubts expressed by a noted scholar about the authenticity of some of the inlays, which are the dominant feature in the decorative scheme. The cross was taken off the market, but when it reappeared recently, Peter Barnet, Michel David-Weill Curator in Charge, thought it warranted further evaluation. The subsequent examination serves as an interesting case study that illustrates the methodology applied in vetting objects under consideration for acquisition, and highlights the resources available at the Museum for elucidating the physical nature of works of art that cannot be sampled or subjected to any form of invasive examination.

The cross is composed of silver-gilt sheet attached to a wooden support and adorned with "faceted" and cabochon inlays. A fragment of the True Cross was mounted at the upper crossing on the principal face, while other relics placed on both sides had been visible either behind rock crystal inlays or through small, circular openings in the silver (Figure 2). In all, the cross originally held ten relics, several of which might still be present. The silver surfaces are richly embellished with a lively, sophisticated patterning created in repoussé, with additional punchwork on the obverse of the sheet, and applied components such as twisted and beaded wire. Examination at low magnification was sufficient to recognize the characteristic appearance of hammered silver sheet and the tool marks associated with burnishing a spongy layer of amalgamed gold, and surface analysis of the gilding with X-ray fluorescence spectrometry (XRF) confirmed the presence of mercury. These technical features, in addition to the idiosyncratic sizes and shapes of the "gemstones", the vacillating tension in the twisted wire, the varying amounts of solder utilized, and the inconsistent use of heat in securing the soldered elements, are indicative of medieval fabrication.

Of the sixty-two inlays originally on the obverse and the thirteen on the reverse, several are now missing. Those remaining are made of glass (Figures 2, 3), apart from three shaped from rock crystal that covered the relics on the principal face, and a single turquoise-colored inlay in the upper crossing on the reverse (Figure 4). During examination of the cross it became apparent that the silver cladding had been removed and remounted several times, either to remove relics or to stabilize the wooden armature. It is quite possible that these interventions resulted in the loss of those inlays now missing, although the majority shows no sign of having been dislodged from their settings.

During the medieval period, the use of glass as a substitute for precious and semi-precious stones became prevalent as the demand for more affordable church furnishings grew. In the twelfth century, Eraclius explains how to mold "gems" out of Roman glass in his De Coloribus et Artibus Romanorum, while Theophilus prescribes the reuse of Roman glass tesserae to create enamels. Analyses undertaken in conjunction with the exhibition "Enamels of Limoges, 1100–1350," presented at the Metropolitan Museum and the Louvre, indeed confirm that the compositions of enamels used in the Limousin during the twelfth century and into the first quarter of the thirteenth century correspond closely to known compositions of Roman glass. These results were obtained primarily through energy-dispersive X-ray spectrometry analyses of polished samples, while open-architecture X-ray diffraction (XRD) and XRF were utilized to identify colorants and opacifiers, and to provide qualitative elemental data for enamels that could not be sampled. On the other hand, no research had been undertaken specifically on glass inlays found on enameled objects from Limoges. Using XRF and open-architecture XRD, both non-destructive techniques, it was established that the compositions of the glass elements on the cross, as well as the nature of the colorants and opacifiers present, are consistent with both Roman glass and Romanesque enamels.

Of particular interest is the large, blue, slightly domed cabochon in the upper crossing on the reverse. Microscopic examination revealed a granular, milky white, glassy substrate overlaid with a translucent turquoise glaze. XRD analyses indicate that the white core material is primarily quartz, while lead oxide was detected in the glaze, where it presumably functioned as a flux. XRF analysis established the colorant of the glaze to be copper-based, and confirmed the presence of lead, along with calcium and sodium, the latter as well present as a fluxing agent. While it was not possible to examine the blue inlay in section, the evidence strongly suggests it is faience. Although this material is generally associated with ancient Egypt, its manufacture continued in the Near East, and faience was still being produced there when the reliquary cross was made. Given the position of Limoges as a major stop on trade and pilgrimage routes, it can be expected that local artists had access to exotic materials, although faience has thus far not been reported in this context.

The material and technological investigations carried out in the Fairchild Center, and the stylistic and historical analysis by Barbara Boehm, Curator in the Department of Medieval Art, were used to build an increasingly strong case supporting the authenticity of the cross, including the glass inlays. This interdisciplinary exchange allowed the work to be dated more precisely and to be placed within a more specific art historical context, and demonstrated that the reliquary cross would fill a lacuna in the Museum's collection of Romanesque liturgical silver. Although little is known about the organization of workshops in medieval Limoges, and in particular whether masters worked exclusively in precious metals, the quality of execution of the objects in the "Enamels of Limoges" exhibition suggests that "goldsmiths" might have worked in copper as well as gold or silver. For every floret or other motif executed in silver, one finds a corresponding detail worked into thin copper sheet, engraved or punched into the thick copper plaques used for champlevé enamelwork, or depicted in enamel. Indeed, the Ambazac Chasse from the treasury of Grandmont, dated between 1180 and 1190, provides some of the more striking parallels to the cross, even though it is executed entirely in gilded copper (Figure 5). All of the decorative metalworking techniques present on the cross can also be found on the chasse, along with the extensive use of glass and faience. Seen in this context, the reliquary cross constitutes an important link between objects of embossed silver that are embellished with "gems", and those executed in copper and decorated with champlevé enamel, studded with settings for cabochons, or engraved with ornamental patterns.

The Reliquary Cross is featured in Recent Acquisitions, A Selection: 2001–2002, MMA Bulletin 60 (Fall, 2002) p. 12, and is currently on display at The Cloisters.

Pete Dandridge is Conservator in the Sherman Fairchild Center, where he began working in 1979, after receiving his M.A. in conservation and a certificate of advanced studies from the Cooperstown Graduate Program in the Conservation of Historic and Artistic Works of Art. Since 1984, he has had primary responsibility for the ivories, enamels, and metalwork in the collections of the Department of Medieval Art and The Cloisters. He has published and lectured on Byzantine ivories, the gilding of silver in Byzantium, Early Christian and Migration Period jewelry, Limoges enamels, and related subjects.