Casket for the crown reliquary of Holy Thorns
Treasury of the cathedral of Saint-Aubain, Musée diocésain de Namur
Case study: Reliquary box (Namur) Coffret-écrin de la couronne-reliquaire de la couronne-reliquaire des saintes Epines, XIIIth century, Namur (inv. n°7)
Materials: wood (oak), leather (lamb or goat), metal (brass, iron), enamel, textile (silk)
Dimensions: diameter 32 cm, height 12,7 cm
Authors of the report: Roosje Baele, Lieve Watteeuw, Christophe Maggi (dendrochronology KIK-IRPA), Zeina Gerardy (independent restorer)
Report date: 21/11/2021
Identification
The box is the case or shrine for the crown-reliquary of the holy thorns relic, conserved in the treasury of the cathedral of Saint-Aubain in Namur (Musée diocésain). In 2011, the crown-reliquary and its box were listed as "Trésors de la Fédération Wallonie-Bruxelles".[1] In 2020, the box and more specific its leather covering was restored. Furthermore, dendrochronological analysis was conducted, which established a provenance and relative date for the wooden plaques.
The crown
The crown-reliquary of the Holy Thorns was designed to house two fragments of Christ's Crown of Thorns and was made in the period after 1206 and before 1218. Following the sack of Constantinople in 1204 by crusader armies of the fourth crusade, relics and precious materials such as gemstones were looted or traded and found their way to Western rulers. In the aftermath of the crusades, the rulers of Constantinople faced economic crisis and therefore many relics were sold or pawned. For example, Baudouin II, Latin emperor of Constantinople, asked his relative Louis IX of France (r. 1240-1261) to come to his aid financially. Louis IX bought 22 precious objects, among them the Crown of Thorns, in the period 1239-1241. He also bought fragments of the relic of the True Cross, among other Passion relics.[2]
Two Holy Thorns, which were originally preserved in the Boukoleon Palace in Constantinople, were sent to Philip I the Noble (1196-1212), Count of Namur by his brother, Henry (1174-1216), Count of Flanders and Hainaut and second Latin emperor of Constantinople. A few years later, it was donated to the collegiate of Saint -Aubain in Namur by Philip I.[3] The donation by Henry is stated in an act of 1205, published in Aigret's Histoire de l'église et du chapitre de Saint-Aubain à Namur of 1881: "Karissimo fratri suo, Philippo marchioni Namucensi, Henricus, frater suus, imperii Romani moderator, salute et fraterne dilectionis affectum." […] "Mitto etiam vobis de sacrosanctis reliquiis imperialis palatii Bucceleonis…".[4] Besides two thorns of the Crown of Thorns, Henry send other relics to his brother Philip, which is also written in the same act of donation of 1205: […] "de spinis corone Domini, de veste purpurea Jhesu Christi, de pannis infantii salvatoris, de linteo quo precinxit se in Cena, de Zona Beate Marie Virginis, de capite Beati Pauli et Beati Jacobi minoris".[5] The donation to Saint-Aubain, then, is written in a letter of 1207 wherein Philip confirms the donation of the relic. A small parchment with the inscription dve spine de corona Dmi, probably written by a 13th-century hand, attests the authenticity of the two thorns. An act of 1723 in the archives of the chapter of Saint-Aubain also confirms its authenticity.[6]
The crown (inv. n° 4) was probably commissioned by Philip I on the occasion of his wedding with Marie de France (daughter of Philip II August, king of France), in a Paris goldsmith's workshop and was made of 8 rectangular hinged plaques, decorated with 8 florets, each placed in the middle of a plaque.[7] On the inside of one of the florets, an old restauration is still visible. The crown was conceived as a portable crown: it could be demounted and stored away safely in case of emergency. Its coating consists of red velour.[8] The borders of the crown are granulated and set with pearls. Each plaque and floret are ornamented with different kinds of precious stones as sapphires, rubies, emeralds, topaz and amethysts, alternating with large pearls and golden rosettes (each consisting of 8 petals).[9] Two florets opposing each other (one in front, the other in the back) contain two thin capsules with lids (embossed in gold) wherein the Holy Thorns were kept. One of the capsules also carried the aforementioned piece of parchment up to 1870. In 1889, the capsules were removed from the crown and placed in a new phylactery. In this way, the relics could be carried more easily during the Feast of the Holy Crown of Thorns in the cathedral.[10]The box
It is assumed that the box (inv. n° 7) was custom-made to conserve and eventually transport the crown-reliquary, in the same area and during the same period. This profane object merely has a practical function but is mainly of interest for its enamel medallions.[11] The octagonal shaped box is constructed with oak wood (Quercus robur L. or Quercus petraea Liebl.) plaques each ca. 12 cm long. Dendrochronological analysis pointed out the wooden plaques are quarterings or semi-quarterings.[12] It is covered by thick brownish leather, held in place with round headed decorative nails, in copper and of three different sizes, but placed symmetrically. The box measures 12,7 cm in height, with a diameter of 32 cm.[13] Twenty-five enameled roundels of 4,5 cm diameter decorate the box, two on each of the eight sides and, nine on the lid of the box, and one more rectangular enamel plaque with concave borders at the lock of the box. The discs are copper gilt champlevé enamel with engraved and gilded figurines surrounded by a lapis blue background (in different hues). The central disc on the lid presents a slightly different finishing with a white decorative border and a polished surface. The scene of this central disc consists of foliage entwined with double filets in blue and white.
A conservation treatment on the box took place in 2020.[14] A conservation strategy was set out on the basis of observation. It pointed out that the leather was vulnerable and extremely delicate to manipulate. Instead of flattening the deformed leather, the conservators chose to soften the deformations in order to adhere the leather to the support. At some areas, the leather was carefully fixed with starch glue (maize) and Japanese paper (K38).[15] The Japanese paper was partially defibered and mixed with the starch glue. It resulted in a paste that could fill the deformations of the leather. As such, the adhering of the interface was optimized between the leather and the support. Aesthetically, the white paper on the visible edges were masked with coloured paper as a final layer. It should be noted that the leather remains fragile at some areas and that future manipulation should be done with extra care.
The enamels
This type of enameled discs, originally from Limoges, were produced in series and commercialized in Europe since the late 12th century. From the end of the 12th century to the 14th century, Limousin enamels were a "trademark" avant la lettre and were characterized by its distinctive blue palette, which one could also find in contemporary illuminated manuscripts or stained glass.[16] Furthermore, the color blue had a spiritual meaning, which was explored by several writers as Hugo de Saint Victor and associated with the Old Testament and heaven.[17] Characteristic for enameling is the combination of painting (via the fusion of glass powder and metal) and sculpture (via the manipulation of copper), which creates a strong visual effect. The technique was chosen for its functionality and aesthetic qualities. Even though it was gilded, it was less expensive than gold.[18] Limoges, however, was not the only center where enamels were produced, also the Meuse and Reine region were known to have manufactured their own enamels. Still, the Limoges enamels proved to be more distributed because it was connected to important trade and pilgrim's routes throughout Europe.[19]
The discs depict Romanesque figures and fantastic creatures: most of the figures depict chimaeras – some with wings, others without wings - besides a winged eagle, a lion, a man holding two serpents with both his hands and a man being attacked by a lion. The hasp on the lid represents a chimaera-like figure with a serpent's head and the body of a bird. Dating from the 13th century, these Roman inspired figures could be considered as late examples. The decoration is considered profane, though Weerth suggested the fantastic creatures could be interpreted as emblems of virtues and vices, the dragons (chimaeras) as guardians of the relic.[20]
Relic boxes
A number of other boxes decorated with enamel plaques have been preserved, for instance the box of Saint Louis conserved at the Musée du Louvre (Ms 253).[21] This rectangular coffret contains 46 discs with weapon of arms and 25 medallions. It is assumed the decoration was realized during the reign of Philip IV the Fair, who received the relics of his grandfather Saint Louis. The box itself originated the abbey of Lys, founded by Saint Louis and his mother Blanche of Castille. The enamels received special attention because of the heraldry, which refers to the family of Saint Louis. The 25 medallions depict various kinds of scenes such as animals, fantastic creatures, hunting scenes and courtly scenes. Another example can be found in the Metropolitan Museum of Art, New York (inv. nr. 17.190.511).[22] This rectangular leather coffret with 30 enameled roundels is also situated in Limoges, ca. 1190. Its hasp shows a pair of winged lizard-like animals; the medallions are encircled with buttons, which have a protective as well as decorative function. The roundels, like the ones of Namur are copper gilt champlevé enamels, and are decorated with fantastic creatures, armed men and floral designs. According to Toussaint the coffret of the Metropolitan presents close resemblances to the coffret of Namur in terms of style and execution and dates the Namur coffret therefore ca. 1200.[23] Jeanmart, however, situates the coffret after 1206 and before 1218.[24] Weerth as well as Courtoy and Schmitz also referred to similar coffrets in the treasury of Aix-la-Chapelle and in the treasury of Tongeren (now the Teseum).[25]
Not much is known about the history of the coffret. Vanrillaer concluded that the precise history since the production of the coffret in the 13th century until the late 19th century remains unclear. From the late 19th century renewed interest in the cathedral's relics did appear, as exhibitions in 1880 and 1888 attest.[26] Aigret, on his turn, included an inventory of the relics of the cathedral from 1572 in his aforementioned Histoire de l'église et du chapitre de Saint-Aubain à Namur wherein the relic of the thorns is mentioned. The origins of the crown are also obscure. Once it was thought the crown of Philip was passed on to his successors, until Jean III, the last count of Namur. However, the documents of 1205 and 1207, as mentioned earlier, did not mention a crown, only the holy thorns.[27] According to Courtoy and Schmitz, the crown (or "la belle corone") is mentioned for a first time in an inventory of 1340.
The inside of the box is lined with a pinned red silk damask with a woven fleur-de-lis pattern, finished with a metal thread braid. This textile is not contemporary and might hide an earlier white colored lining (of which no evidence is visible at this moment).[28]
In 2020, the researchers of KIK-IRPA (Royal Institute for Cultural Heritage) Brussels conducted a dendrochronological analysis on the reliquary box.[29] Samples were taken of the lower margins of 6 of 8 vertical plaques. Furthermore, the plaque of the cover and two horizontal borders were also accessible for analysis. The plaques on the bottom that contain sapwood were unfortunately not accessible for dendrochronological research. In total 7 of the 10 plaques were carefully analyzed. The samples contained 8 series of tree rings; they were summarized and identified according to the dendrochronological code.[30] First some measuring points were carefully cleaned with a brush, so that the tree rings could be seen more clearly. Further, the tree rings were registered with a CANON EOS D200, added with a macro lens and a measurement in millimeters. The density of the tree rings was analyzed with the macro images in AdobeTM and PhotoshopTM and then exported in a vectorial format. The data were then reconstructed and converted into a "Besançon" format with specialized software. The dating (relative and absolute) was visualized in a chart with Dendron IV (version 20150221) software. It was estimated that 3 plaques originate the same tree; their data were categorized in individual series and were dated (together with the last tree ring) 1193. This date also revealed that the tree used for the plaques originated the region of the Seine and Meuse.[31] Because the analyzed plaques lacked any sapwood, a possible date for the cutting of the tree could not be determined. However, a terminus post quem for the manufacture of the box was appointed after 1197.[32][1] See the "Liste des biens classes: beaux-arts/ orfèvrerie", Portail official de la Fédération Wallonie-Bruxelles, accessed 28 July 2020, http://www.patrimoineculturel.cfwb.be/index.php?id=beaux-artsorfverie.
[2] See Klein, Holger A. "Sacred Things and Holy Bodies. Collecting Relics from Late Antiquity to the Early Renaissance." In Treasures of Heaven: Saints, Relics and Devotion in Medieval Europe, edited by Martina Bagnoli, Holger A. Klein, C. Mann et al, 58-59. London: British Museum, 2010. The acquired relics were housed in Paris, the Sainte-Chapelle. A reliquary was made in the 1240s, the so-called Grande Châsse, and displayed behind the altar of the chapel. The Crown of Thorns had a highly status and was interpreted as the Salvation of humankind. Its form was conceived as royal and related to the Kingdom of God. The acquisition of the Crown by France was seen, then, as an alliance with God. See in detail Bozoky, Edina. "Saint Louis, ordonnateur et acteur des rituels autour des reliques de la Passion." In La Sainte-Chapelle de Paris. Royaume de France ou Jérusalem céleste?, edited by Christine Hediger, 28-29. Turnhout: Brepols, 2007.
[3] Courtoy, Ferdinand and Jean Schmitz. Mémorial de l'exposition des trésors d'art: Namur 1930. Namur, 1930, 13. Klein, Holger A. "Eastern Objects and Western Desires: Relics and Reliquaries between Byzantium and the West." In Dumbarton Oaks Papers, 58 (2004): 283-314. Bozoky mentions the crown, inserted with the two Holy Thorns, was used for the coronation of Henry in 1206, emperor of Constantinople. Bozoky, 28. In relation to the status of the relics, see also George, Philippe. Reliques. Se connecter à l'au-delà, Paris: CNRS Editions, 2018, 314. About Philip I, see De Borchgrave, Emile. « Philippe Ier de Namur. » In Biographie nationale de Belgique, vol. 17. Brussels : Académie royale de Belgique, 1903, 316-319, https://www.academieroyale.be/fr/la-biographie-nationale-volumes-detail/oeuvres-2/biographie-nationale-2963/, accessed 9 December 2020. About Henry, second Latin emperor of Constantinople, see Wauters, Alphonse. « Henri de Hainaut ou de Flandre. » In Biographie nationale de Belgique, vol. 9. Brussels : Académie royale de Belgique, 1887, 178-182, https://www.academieroyale.be/fr/la-biographie-nationale-volumes-detail/oeuvres-2/biographie-nationale-2955/, accessed 9 December 2020.
[4] Aigret, N.J., Histoire de l'église et du chapitre de Saint-Aubain à Namur. Namur: Imprimerie de veuve F.-J. Douxfils, 1881, 627-631.
[5] Aigret, 627-631. Klein, "Eastern Objects and Western Desires", 302. This fragment was translated by Klein as follows: […] "of the purple vestment of Jesus Christ, of the swaddling clothes of the Savior, of the linen with which he girded himself at the Supper, of the girdle of the Virgin, [and] of the head of St. Paul and St. James the Younger."
[6] Aigret, 629. This act refers to the parchment fragment: "[…] cum parvo pergameni fragmento, super quo scriptum inspicitur De spinis Coronae Dni, in altera vero duas sacras spinas spineae Coronae Dni sat longas et grossas, bene virentes et integras…". A reproduction of the parchment fragment was published in Lanotte, A., Orfèvreries du trésor de la Cathédrale de Namur. (cat. exp., Namur, siège du Crédit communal de Belgique pour la province de Namur, 1-23 nov. 1969), Bruxelles : Crédit communal, 1969, 24-26, n°3 and in Collet, Emmanuel. De beschermde kunstschatten van de kathedraal van Namen. Brussel: Koning Boudewijnstichting, Fonds Pierre François Tilmon, 2013, 32, https://en.calameo.com/read/0037220505c5dc7557948, accessed 8 December 2020.
[7] Collet, 7. In the past, it has been suggested the crown was meant to be passed on to the successors of Philip I. See Aigret, 59-60 and De Hautregard, Lambert François Joseph. Notice sur la Cathédrale de Namur. Namur: A. Wesmael-Legros, 1851, 17-18, https://books.google.be/books?id=-4hBAAAAcAAJ&printsec=frontcover&hl=nl&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false, accessed 9 December 2020. Images of the crown can be consulted on Balat – KIK-IRPA, accessed 27 July 2020, http://balat.kikirpa.be/object/10026537. Courtoy and Schmitz, 13.
[8] According to Weerth this coating ("un bourrelet intérieur de velours rouge", 392) has also a practical function, in that it would be less painful for the bearer's head while wearing it. Weerth, Ernst aus'm. "La couronne de la Cathédrale de Namur et son écrin, attribués aux deux premiers empereurs latins de la maison de Flandre." In Annales de la Société archéologique de Namur, IX (1876): 394-405. The article was published together detailed drawings of the coffret and reliquary crown. Collet, 32-34.
[9] One of the blue stones on the plaques, however, appears to be a "recycled" exemplar. See the image in Collet, 26-27.
[10] On cit. Collet, 33. De Hautregard, 18, mentions the crown is shown every year, "au rit propre, double 2e classe, le vendredi après le dimanche de Quasimodo", i.e., Second Sunday of Easter. See "Quasimodo", Liturgie et sacrements, accessed 9 December 2020, https://liturgie.catholique.fr/lexique/quasimodo/.
[11] Collet, 34; Nickers, J. and P. Sosson. Le trésor de l'église cathédrale de Saint-Aubain à Namur. Namur: Imprimerie V. Delvaux, 1906, 26-28; Courtoy and Schmitz, 14; Vanrillaer, Ludovic. Un écrin sous-estimé au sein du Trésor de la cathédrale Saint-Aubain de Namur : le coffret des Saintes Épines. Analyses technique, morphologique et iconographique accompagnées d'une typologie des coffrets. Faculté de philosophie, arts et lettres, Université catholique de Louvain, 2017. Prom.: Dekoninck, Ralph; Lefftz, Michel, 16.
[12] Dr. Christophe Maggi, "Rapport de synthèse d'analyse dendrochronologique", KIK-IRPA Brussels, 01/03/21, 3.
[13] Nickers and Sosson, Courtoy and Schmitz mention 29,5 cm diameter. Lanotte, Jeanmart, Toussaint and Vanrillaer all mention 32 cm. See Jeanmart, Jacques. "17. Ecrin de la couronne-reliquaire du Saintes Epines." In Dialogues avec l'invisible: l'art aux sources de l'Europe. Oeuvres d'exception issues de la communauté françaises de Belgique (VIIIe-XVIIe siècle), edited by Jacques Toussaint. Namur: Société archéologique de Namur, 2010. Toussaint Jacques. Émaux de Limoges, XIIe-XIXe siècle. Namur : Société Archéologique de Namur, 1996, 61-62.
[14] Zeina Salloum Genadry, "Rapport de Traitement 25/07/2020"
[15] Japanese paper by La Route de Papier, Genadry, "Rapport de Traitement 25/07/2020".
[16] On cit. Boehm, Barbara Drake. "Opus Lemoviscense: The Taste for and Diffusion of Limousin Enamels." In Enamels of Limoges 1100-1350, edited by Marie-Madeleine Gauthier, Bernadette Barriere, Dom Jean Becquet et al, 40. New York: The Metropolitan Museum of Art, 1996, https://books.google.be/books?id=qrHe4eF1NRkC&printsec=frontcover&hl=nl&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false, accessed 9 December.
[17] Boehm, 41, according to Boehm this spiritual meaning possibly underlines the taste for blue enamels. Collet, 26.
[18] Boehm, 41-42.
[19] Their popularity is also related to the taste of certain highly influential individuals in France and England (e.g., the Plantagenets) with considered political influence. See the overview and analysis of Boehm, 42-46.
[20] Weerth, 393-394; Aigret, 59; Collet 26.
[21] See "Coffret dit 'de Saint Louis'", Musée du Louvre, accessed 27 July 2020, https://www.louvre.fr/oeuvre-notices/coffret-dit-de-saint-louis . The comparison was first made by Courtoy and Schmitz, 14. For a detailed description of this coffret, see the catalogue entry by Boehm, Barbara Drake and Michel Pastoureau, « The Coffret of Saint Louis. » In Enamels of Limoges 1100-1350, edited by Marie-Madeleine Gauthier, Bernadette Barriere, Dom Jean Becquet et al, 360-363. New York: The Metropolitan Museum of Art, 1996.
[22] See "French. Coffret ca. 1190", The MET, accessed 27 July 2020, https://www.metmuseum.org/art/collection/search/464480. For a detailed description of this coffret, see the catalogue entry by Boehm, "Coffret" in Enamels of Limoges 1100-1350, edited by Marie-Madeleine Gauthier, Bernadette Barriere, Dom Jean Becquet et al, 154-155. New York: The Metropolitan Museum of Art, 1996.
[23] See Toussaint, 61.
[24] See Jeanmart, "17. Ecrin de la couronne-reliquaire du Saintes Epines."
[25] See the extensive description of the coffret of Aix-la-Chapelle by Weerth, 395-398. The one of Tongres, however, was only passingly mentioned by Courtoy and Schmitz, 14.
[26] See Vanrillaer, 16. See the section "Exhibitions" on p. 5.
[27] See the documents in appendix of Aigret, 627-631.
[28] Jeanmart, "17. Ecrin de la couronne-reliquaire du Saintes Epines."; Nickers and Sosson, 17, "Anciennement ce coffret était double d'une étoffe blanche qui fut dans la suite remplacée par un damas de soie rouge du XVIIe siècle." The authors seem to be the only one mentioning this earlier white lining.
[29] Dr. Christophe Maggi, "Rapport de synthèse d'analyse dendrochronologique", KIK-IRPA Brussels, 01/03/21.
[30] Dendrochronological code of the KIK-IRPA which attributes a specific number to the object, the individual sample and to the location of where the sample was taken. See in detail the report of Dr. Maggi on pp. 4-9. Dr. Christophe Maggi, "Rapport de synthèse d'analyse dendrochronologique", KIK-IRPA Brussels, 01/03/21.
[31] The tree rings were registered on the narrow sides of the cover and then synchronized. Individual series were compared visually. The dendrochronological data were individually compared with the reference system of KIK-IRPA in order to establish a date and origin of the wood. The results determined a vast geographical region. See more in detail the report of Dr. Maggi, 5.
[32] A minimum of sapwood was included in the calculation, namely 4 tree rings. This resulted in the following measurement for the cutting of the tree: 1193 (i.e. the last tree ring of the box) + 4 tree rings, resulting in 1197 as a terminus post quem. See Dr. Christophe Maggi, "Rapport de synthèse d'analyse dendrochronologique", KIK-IRPA Brussels, 01/03/21, 5-6.
Exhibitions
Brussels 1880 – Exposition Générale des objets d'art religieux
Brussels 1888 – Rétrospective des arts industriels
Namur 1995 – Émaux de Limoges
Beaune 2006 - Trésors de Cathédrales d'Europe. Liège à Beaune
Bibliography
Aigret, N.J., Histoire de l'église et du chapitre de Saint-Aubain à Namur. Namur: Imprimerie de veuve F.-J. Douxfils, 1881, 58-61, 627-631.
Bagnoli, Martina, Holger A. Klein, C. Mann et al. Treasures of Heaven: Saints, Relics and Devotion in Medieval Europe. London: British Museum, 2010.
Boehm, Barbara Drake. "Opus Lemovicense: The Taste for and Diffusion of Limousin Enamels." In Enamels of Limoges 1100-1350, edited by Marie-Madeleine Gauthier, Bernadette Barriere, Dom Jean Becquet et al, 40-47. New York: The Metropolitan Museum of Art, 1996. https://books.google.be/books?id=qrHe4eF1NRkC&printsec=frontcover&hl=nl&source=gbs_ge_summary_r&cad=0 - v=onepage&q&f=false, accessed 9 December 2020.
Bozoky, Edina. "Saint Louis, ordonnateur et acteur des rituels autour des reliques de la Passion." In La Sainte-Chapelle de Paris. Royaume de France ou Jérusalem céleste?, edited by Christine Hediger, 19-34. Turnhout: Brepols, 2007.
Collet, Emmanuel. De beschermde kunstschatten van de kathedraal van Namen. Brussels: Koning Boudewijnstichting, Fonds Pierre François Tilmon, 2013, 15-19, 26, 32-34. https://www.kbs-frb.be/nl/Virtual-Library/2013/307404, accessed 9 December 2020.
Courtoy, Ferdinand and Jean Schmitz. Mémorial de l'exposition des trésors d'art: Namur 1930. Namur, 1930, 14.
De Borchgrave, Emile. "Philippe Ier de Namur." In Biographie nationale de Belgique, vol. 17. Brussels: Académie royale de Belgique, 1903, 316-319, https://www.academieroyale.be/fr/la-biographie-nationale-volumes-detail/oeuvres-2/biographie-nationale-2963/, accessed 9 December 2020.
De Hautregard, Lambert François Joseph. Notice sur la Cathédrale de Namur. Namur: A. Wesmael-Legros, 1851, 18. https://books.google.be/books?id=-4hBAAAAcAAJ&printsec=frontcover&hl=nl&source=gbs_ge_summary_r&cad=0 - v=onepage&q&f=false, accessed 9 December 2020.
De Mély, Fernand. "Reliques de Constantinople: La Sainte Couronne d'Epines." In Revue de l'art chrétien, 42, 4 (1899), https://archive.org/details/revuedelartchr1899lill/page/2/mode/thumb, accessed 20 July 2020.
Gauthier, Marie-Madeleine, Bernadette Barriere, Dom Jean Becquet et al. Enamels of Limoges 1100-1350. New York: The Metropolitan Museum of Art, 1996, 78-82, 154-155, 360-363.
George, Philippe. Reliques. Se connecter à l'au-delà, Paris: CNRS Editions, 2018, 314.
George, Philippe. Trésors de Cathédrales d'Europe. Liège à Beaune. (cat. exp., Beaune, 19 nov. 2005 – 19 mars 2006), Paris : Somogy, 2005.
Jeanmart, Jacques. "Un musée trop peu connu. Le musée diocésain à Namur." In Le Guetteur Wallon. Art et Savoir, 77, 1 (2001): 5-9.
Jeanmart, Jacques. "17. Écrin de la couronne-reliquaire des Saintes Épines." In Dialogue avec l'invisible: l'art aux sources de l'Europe. Œuvres d'exception issues de la communauté françaises de Belgique (VIIIe-XVIIe siècle), edited by Jacques Toussaint. Namur: Société archéologique de Namur, 2010.
Klein, Holger A., "Eastern Objects and Western Desires: Relics and Reliquaries between Byzantium and the West." In Dumbarton Oaks Papers, 58 (2004): 283-314.
Lanotte, A., Orfèvreries du trésor de la Cathédrale de Namur. (cat. exp., Namur, siège du Crédit communal de Belgique pour la province de Namur, 1-23 nov. 1969), Bruxelles : Crédit communal, 1969, 24-26, n°3.
Nickers, J. and P. Sosson. Le trésor de l'église cathédrale de Saint-Aubain à Namur. Namur : Imprimerie V. Delvaux, 1906, 26-28.
Nicol, Donald MacGillivray. Byzantium and Venice: A Study in Diplomatic and Cultural Relations. Cambridge: Cambridge University Press, 1988, 168-170.
Toussaint, Jacques. Émaux de Limoges, XIIe-XIXe siècle. Namur: Société Archéologique de Namur, 1996, 61-62.
Vanrillaer, Ludovic. Un écrin sous-estimé au sein du Trésor de la cathédrale Saint-Aubain de Namur : le coffret des Saintes Épines. Analyses technique, morphologique et iconographique accompagnées d'une typologie des coffrets. Faculté de philosophie, arts et lettres, Université catholique de Louvain, 2017. Prom. : Dekoninck, Ralph ; Lefftz, Michel.
Wauters, Alphonse. "Henri de Hainaut ou de Flandre." In Biographie nationale de Belgique, vol. 9. Brussels: Académie royale de Belgique, 1887, 177-182, https://www.academieroyale.be/fr/la-biographie-nationale-volumes-detail/oeuvres-2/biographie-nationale-2955/, accessed 9 December 2020.
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Internet sources
"Coffret-écrin de la couronne-reliquaire des Saintes Epines", Balat – KIK-IRPA, accessed 20 July 2020, http://balat.kikirpa.be/object/10026545.
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