The feathered bishop’s miter and infulae (liturgical headgear and lappets) of the Museo degli Argenti, Florence, are one of seven such sets of Catholic regalia known from Mexico, perhaps one of a group of miters made in the Michoacán area of Mexico that were taken to Spain in 1547 for delivery to Charles V, and for distribution among clergy (Figure 1).1 The Argenti miter is reported as having been presented by Charles V to Pope Clement VII.2 The closest parallel to the Argenti miter and infulae is the set that arrived at the Monastery of San Lorenzo de Escorial in 1576, part of a commission by Felipe II. The Argenti miter and infulae eventually became part of the collection of Ferdinando I de’ Medici, the Grand Duke of Tuscany.3 Corinna Tania Gallori reports that the miter of Argenti in Florence, along with the miters in the Duomo in Milan, the Hispanic Society in New York, El Escorial in Spain, and Lyons in France, all contain monograms representing the Holy Names of Jesus and Mary, suggesting inspiration from earlier Christian sources.4 Each of these sets includes feathered decoration on a woven textile support.
Many authors who examine liturgical garments made by Mexican featherworkers (amantecas) for Spanish friars in New Spain remark on the diplomacy, sensitivity, and skill these commissions must have required.5 These Indigenous featherworkers employed Aztec materials and techniques for the production of Catholic ceremonial garb, basing the motifs on what is frequently noted to be European graphic arts. Despite these origins, Alessandra Russo declares these works to have been a totally new invention for both Indigenous and Spanish practitioners in New Spain.6 The material intricacies of the feathered garments support the argument that the amantecas did not slavishly follow Flemish, German, or Italian print designs that serve as sources, as has been suggested by Elena Isabel Estrada de Gerlero and other scholars.7 In this paper I will discuss details of the construction of the spectacular bishop’s miter and infulae from the Museo degli Argenti.8 They manifest clear evidence that the featherworker took considerable liberty in manipulating materials for an intended effect that is highly organized yet jewellike, with much attention to changes in the appearance of the feathers produced by changes of the viewing angle, as has been described by contemporaneous chronicler Bartolomé de las Casas.9
We owe much of what we know about the construction of Mexican feather mosaics to Bernardino de Sahagún’s images and text in book IX of the Florentine Codex, a 1576–78 document of Indigenous practices recorded in Spanish and Nahuatl, as well as textual reports of other Spanish chroniclers in Mexico in the sixteenth century.10 Sahagún and his informants list the naturally colored feathers of eighteen birds indigenous to Mexico and used by amantecas to create brilliant mosaics. In recent times, Mexican feather mosaic techniques have been explored by the French anthropologist Pascal Mongne, Mexican conservator Rosa Lorena Román Torres, and conservation scientist Sylvie Colinart and her colleagues. These studies have been carried out in France on the exquisite feathered wood panel depicting the Mass of Saint Gregory in the Musées des Jacobins in Auch and the feathered wood triptych of the Crucifixion with Saint Jerome and Saint Francis in the Musée National de la Renaissance in Écouen, and in Mexico on the Cristo Salvador del Mundo in the Museo Nacional del Virreinato, a feathered mosaic on a stretched fabric support. A total of four Catholic feathered wood panels produced in Mexico during the sixteenth, seventeenth, and eighteenth centuries and now housed in museums in France have been studied and conserved by Mongne with additional study of the triptych by Colinart.11 The Cristo Salvador del Mundo is dated to approximately 1550, with the composition attributed by Estrada de Gerlero to prints dating to 1477 and 1503, respectively.12 The Mass of Saint Gregory panel is firmly dated to 1539 in the framing text, and was commissioned by Nahua noble and governor of Mexico City Diego de Alvarado Huanitzin (nephew and son-in-law to Moctezuma II) and supervised in its production by Fray Pedro de Gante, a Franciscan who supported Indigenous arts as early as 1524.13
As a set of garments produced on a flexible fabric support, we might guess that the feathered miter and infulae from the Museo degli Argenti would have more in common technically with the Cristo Salvador del Mundo featherwork on stretched fabric than with the either the triptych or the Mass of Saint Gregory produced on wood panels. While much is known about colonial feather mosaic techniques from Sahagún, and from technical examination of the three works published by authors previously cited, very little has been published about textile-based feathered miters. Based on the documentation assembled in this current study, including images captured under diffused and raking light, photomicrographs, infrared reflected images, and X-radiographs, the miter and infulae mosaic bear both similarities to and differences from the other works. In the case of the Museo degli Argenti miter and infulae, these techniques reveal the artistic ingenuity of the creators.
In the observed techniques for the miter and infulae, the individual feathered segments are adhered to a thin and transparent plant fiber paper support (Figure 2), which itself was either adhered directly to other feather “tesserae” or secured to a heavier paper before being attached to a fabric support (Figure 3). These techniques resemble what Mongne reports for the Mass of Saint Gregory and for the triptych, except that in those cases the heavier paper is adhered to wood, a planar and moderately inflexible support. Mongne also reports a heavy reliance on tracing through the transparent paper in order to replicate motifs presumably derived from prints. Román Torres reports that feathers used on the Cristo Salvador del Mundo are adhered to a thin and transparent cotton paper support, which is further adhered to a heavily sized support of maguey fiber paper, then onto a textile stretched onto a frame perhaps made out of cane, also producing a flat support.14 In the case of the miter and infulae, the feather “tesserae” are heavily layered and far from planar, producing instead a three-dimensional appearance (Figure 4)
In addition to these dimensional differences, techniques used in the examination of the miter and infulae show numerous examples of preparatory marks made to permit the positioning of design elements, and to create drapery and other defining characteristics. Evidence suggests both a highly developed underdrawing used in the preparation of the miter and infulae, but also that the featherworker departed from following this underdrawing in the feather execution. Further evidence is also provided of overdrawing applied to and across feathered areas in order to reinforce the design, indications that the amanteca was adapting the design while working with the feathers.
The use of underdrawing on Mexican feathered mosaics has been more speculated upon than found; however, in the case of the miter and infulae from the Museo degli Argenti, underdrawing is both confirmed and elaborate (Figures 5 and 6).15 However, the reliance on the underdrawing is not slavish, conflicting with the observations of Franciscan friar Toribio de Benavente, also known as Motolinía, who in 1541 reported, “If to these amantecas they give a good sketch or pattern, the amantecas produce equally good feather-work.”16 Román Torres rightly reports the challenges of translating graphic images to featherwork in terms of both medium and scale, as the feathered mosaics are often larger than their graphic inspirations. In her own work on the Cristo Salvador del Mundo, Román Torres observed red underdrawing (suggested as possibly cochineal or brazilwood) visible on the cotton twill support.17 Román Torres’s work provides excellent material identification but does not dwell on underdrawing.
Using two different infrared reflectography techniques most often employed by painting conservators to detect carbon-based chalk or ink drawings below a paint layer on a white ground, extensive underdrawings of the Argenti miter and infulae were detected. The techniques used include a modified camera sensitive from 300 to 1000nm with an 87c filter in front the lens (80 percent transmittance at 900nm to 90 percent at 1000nm), and an InGaAs sensor camera sensitive from 800nm to 1700nm. As both techniques revealed evidence of underdrawing, it is most likely the region of overlap—that is, 800 to 1000 nm—that was most effective for revealing reflectance.
It was uncertain whether the infrared energy emitted by tungsten halogen lamps, paired with specialized capture, would be able to penetrate featherwork to detect underdrawing. Colinart et al. used an infrared image of the triptych of the Crucifixion and Saint Jerome and Saint Francis, but those authors describe only the appearance of the carbon-black paint on the frames.18 The principle of revealing underdrawing relies on the infrared reflectance of the drawing media, as well as the ability of the infrared energy to penetrate the pigments and binder, in the case of a painting. While the influence of pigment particle size, ratio of pigment to binder, paint layer thickness, and pigment chemistry have been studied to optimize the capacity of infrared imaging to reveal concealed details on paintings, such work has not been conducted in the case of featherwork.19 The interaction of feathers with near-infrared energy (700 to 2500 nm) depends on plumage color and microstructure, with dark feathers absorbing infrared and light feathers reflecting, to contribute to the thermal insulation provided by feathers on the living bird.20 According to bird biologists studying the effect on feathers of solar radiation, 50 percent of which is infrared: “In dark plumages, 90% of the radiation absorption occurs in the upper 20% of the coat and none of the radiation penetrates beyond the upper 25% of the coat. In contrast, in light plumages, a full 10% of the radiation intercepted penetrates through more than 80% of the coat before it is absorbed.”21 It is therefore not surprising that only paler featherwork permits the penetration of infrared.
In the case of the miter and infulae, techniques applied were successful in capturing both underdrawing and overdrawing made following adhesion of feathers. Infrared energy was able to penetrate the paler-colored feathered surfaces to reveal considerable underdrawing, as can be seen in Figures 5–7. While the technique was unable to image underdrawing continuing below darker feathers, it most certainly continues there. Underdrawing is used to achieve symmetry, and to propose the position of motifs. Photomicrographs further captured marks added after the attachment of feathers (Figure 8).
Both organized and randomly oriented feathers are observable on details from the miter and infulae (Figure 9, see Figure 8). The contrast between the regular orientation of feather structures, including the barbs (parallel elements that project 45 degrees from the feather shaft) and the barbules (tiny hooks that connect the barbs), and the more randomly oriented partial feathers observed in broader areas illustrate further decisions that the featherworker made. The construction of the Argenti miter and infulae makes substantial use of vertically directed and trimmed barbs for discrete elements, including figures, borders, clouds, foliage, and architecture. This practice creates motifs comprised of intensely colored and organized barbs with sharp edges. For background areas, less trimmed feathers, including barbs and barbules, are freely overlapped with a less strict indication of directionality. As I have noted elsewhere, these background feathers are likely to be those of smaller birds such as hummingbirds (Colibris sp.); such iridescent feathers hold their iridescence in the tiny hooks or barbules, a phenomenon only detectable at the feather tips. Overlap on the bird produces the appearance of fully iridescent plumage, as the dull proximal portions are concealed.22 The choice to use more of the feather and to overlap clearly represents artistic intent by the amanteca.
The application of infrared reflected image capture along with micrographic study furthered our knowledge of the active role of the amanteca in the design and execution of a Mexican feather mosaic. The relation between underdrawing and overdrawing and the applied feathers in the Argenti miter and infulae provide evidence of the amanteca’s role in artistic decision making. While the Christian designs likely originated from European prints, the current examination indicates that the application of featherwork only loosely relied on the underdrawing for organization of motifs.
In the case of this examination, broadband or wide-range infrared examination was performed, which suggests that the underdrawing detected is based on a carbon pigment such as is found in carbon-black chalk, paint, or ink, and not cochineal or brazilwood as suggested by Román Torres for the Cristo Salvador del Mundo. Román Torres further observes that underdrawing for that work was applied to the cotton twill fabric, while line work in the case of the Argenti miter and infulae is uninterrupted by weave patterning and is observed to be directly on a paper layer applied to the textile support. Such variations may be the result of differences in production methods employed for feathered canvases versus liturgical garments.
While it is unlikely that specific techniques will be designed for imaging underdrawings beneath featherwork, it is possible that developments made in the examination of paintings will benefit further studies applied to Mexican featherwork. Researchers are currently working on narrow-band infrared imaging as a tool to capture media beyond carbon-based materials, and as a method capable of penetrating paint layers formerly opaque to broadband infrared detection.23 Techniques that permit control over capture of depth and width, that is, mapping and spatial measurements, are further advancing the possibilities for understanding the role of planning in the completion of complex artworks such as Mexican feather mosaics.
The application of X-radiography to feather mosaics, for example by Colinart et al. for the triptych of the Crucifixion with Saint Jerome and Saint Francis, assisted in imaging metal hinges, metal leaf applications, and lead-containing pigments.24 In the case of the Argenti miter and infulae, X-radiography effectively imaged where fabric sections are joined and overlap. The metal thread borders were expectedly radio-opaque, but with the miter, only concealed details of the textile were revealed with X-radiography.
The opportunity to document the Museo degli Argenti’s miter and infulae arrived when these precious garments were loaned to a museum with microscopes and imaging technology. Staff at both the lending and borrowing museums generously extended the time of the miter and infulae off exhibit and before packing for travel, and made tools and staff available for this examination. These opportunities permitted the discovery of the artistic invention of the amantecas in the production this miter and infulae. Further use of these evolving techniques, not even previously considered applicable to featherwork, stand to enlighten us about the amantecas’ relationship to Christian sources during the colonial period.