Analyses of Early Medieval Stained Window Glass From the Monastery of Baume-Les-Messieurs (Jura, France)

Abstract

The collection of early medieval window glass found in the abbey of Baume-les-Messieurs (Jura, France) is exceptional because it dates to the end of the eighth century, and due to the number of fragments as well as their state of conservation. Different colours and forms have been identified. These pieces are a rare opportunity to address the glass craft, its recipes and techniques for a phase of its history that has remained little known. Analyses in PIXE-PIGE prove that, in addition to fragments from two soda glass items, the pieces are made from wood-ash glass. Most of them probably came from the same production and the raw material is present in the region. At this early stage of wood-ash glass production, the glassmakers had mastered the glass as well as the colour processes.

Regional patterns in medieval European glass composition as a provenancing tool

“…The present meta-analysis of legacy data focuses on forest glass of the 12 th through the 15 th centuries, a period which coincides with the development of Gothic architecture and the related surge in glass production through to the end of the medieval period (Philippe, 1998;Wedepohl, 2003). Compositional data for forest glass predating this period are more scarce and it is less well-defined chemically (Barrera and Velde, 1989;Wedepohl and Simon, 2010; for early forest glass data, see also Sterpenich and Libourel, 2001;Van Wersch et al, 2016) and archaeological evidence for glass production is similarly comparatively scarce before the 12 th century (Foy, 2000;Philippe, 1998).…”

Thermodynamic insight into the evolution of medieval glassworking properties

“…From the eighth to ninth centuries, the flux used in the Mediterranean area to make soda‐type glasses was changed from natron (mineral soda) to Na 2 O‐rich costal plant ashes . As early as at the end of the eighth century, an intense glass production started in Northern Europe using ashes from ferns and wood as flux, leading to potash‐lime silicate glasses . These later compositions may be classified into two main categories: (i) high CaO, low MgO and K 2 O glasses (high‐lime low‐alkali glass) with ~5 wt% K 2 O and 20 wt% CaO, and relatively high SiO 2 content ~60 wt%, that we will refer to as “lime‐type” glasses; (ii) low CaO, high K 2 O and MgO glasses (low‐lime high‐magnesium) with a K 2 O/CaO weight ratio close to 1, and a lower SiO 2 content ~50 wt%, that we will refer to as “potash‐type” glasses.…”

Recent progress in instrumental techniques for architectural heritage materials

“…Sensitivity usually reaches a few μg/g for transition metal elements, and several hundred of μg/g for the major elements. For example, the stain glass windows from the Baume-les-Messieurs monastery are typical for history of glass [13]. 41 representative samples were detected by the PIXE-PIGE analytical method to identify natron glass (2 pieces) and wood-ash glass (39 pieces) of 8th century.…”

“…More importantly, the restoration and conservation of the historic architecture which is as an integral constituent of human civilization turn out to be a global and worldwide issue [1][2][3][4]. As for the architectural heritage preservation, what must be taken into account are the factors which deal with issues of extending the life and preserving the authenticity and integrity of building characteristics such as design style and the constituent materials including sandstone [5][6][7][8], brick [9][10][11], glass [12][13][14][15], wood [16,17], painting layer [18][19][20], mortar [21][22][23][24], wall material [25,26], etc. Furthermore, in addition to the original material itself, ancient building materials have been suffering from decay and intervention in different processes [27].…”