Mitre of Jacques de Vitry

Art Historical background

The treasury of Oignies, kept in Namur is a splendid treasure trove of religious silverware, relics and valuable objects, dating back to the 13th century. The treasury is linked to the Augustinian Priory where Marie of Oignies stayed during her life ( Maria Ogniacensis, 1177-1213). Her friend, confessor and hagiographer Jacques de Vitry (c. 1165-1240) played an important role in the growing veneration for de saint woman and the wealth of the Priory.^[1] After becoming a dean of the College of Cardinals, Jacques de Vitry died in Rome in 1240. Before his death Jacques indicated that he wanted to be buried at Oignies, near Marie, and he endowed the priory with 1,500 silver pounds, silk textiles from the Orient, his personal ecclesiastical ornaments, relics of saints, and a large number of books. According to his last wishes, his remains were transferred to Oignies, where they were placed next to the blissful Mary of Oignies.^[2] The community cherished the remains of the saint and Jacques de Vitry carefully during centuries. After the destruction of the priory of Oignies during the French Revolution, the treasure was entrusted in 1818 to the Sisters of Our Lady of Namur. In 2010 the treasury became part of the collection of the King Baudouin Foundation.^[3] Several items from bishop Jacques de Vitry are still in the treasury of 0ignies: a portable altar, two bishop's miters, a maniple, a part of an ivory cross, and two episcopal rings with sapphires, all parts of the bishops ecclesial ornaments.

Micro-invasive analysis for this type of multilayered object is mainly limited by the possibility to collect a sample. However, due to the poor condition of some fragments, a few micro-samples could be collected. The identification of the fibers is based on the examination of the fiber morphology by optical microscopy in transmitted and/or polarized light. The dye composition is analyzed by high pressure liquid chromatography coupled with a photodiode detection system (HPLC-DAD). A complete examination of the metal thread composition, identifying not only the metal but also the potentially present textile core, dyed or not, is carried out using scanning electron microscopy and energy dispersive X-ray detection (SEM-EDS). This gave the following results:

The threads of the highly degraded beige / uncoloured main fabric, have been identified as degummed silk (Bombyx mori L.) filaments. The red lining fabric is also composed of silk, colored by the use of madder root (Rubia tinctorium L.). The brown-black remains of a small ribbon on the outside of the fanons were dyed black with tannins and ferrous sulphate and alum, a known method until the late 18th century. However, the use of iron sulphates had disastrous effects on the silk, so that these black ribbons have almost completely disappeared today.

HPLC-DAD Dye composition of green/ochre yarns, chromatogram at 255 nm

The green/ochre yarns forming part of the central decoration with metallic threads were dyed with a combination of blue and yellow dye sources. Based on the presence of the compounds indigotin and indirubin, the blue source is either indigo (Indigofera sp.) or woad (Isatis tinctoria L.), and the detection of the yellow compounds luteolin and apigenin indicates the use of plants such as weld (Reseda luteola L.), sawwort (Serratula tinctoria L.) or chamomile (Anthemis sp.).

Transmitted light microscopy of silk filaments in the background tissue

The metal thread sample taken from the central decoration consists of a silver lamella which has been gilded on the outer surface. This strip has been wound in the s direction around a textile core of silk threads. The central silk thread was almost completely covered by the silver lamella. It was dyed yellow with weld, sawwort or chamomile. The current dark color of the metal is due to corrosion caused by the formation of silver chlorides. This type of silver thread (guilded or not) was well known in the Middle Ages.