Multi-disciplinary Investigation of the Windows of John Thornton, focusing on the Great East Window of York Minster

Twenty-seven samples of glass from panel 2e of John Thornton’s Great East Window (1405–1408) at York Minster have been analyzed using energy dispersive x-ray analysis in the scanning electron microscope. This paper highlights our findings. Inserts and replacements of early modern and medieval glass have been identifi ed. White (colorless) and colored medieval glass differ significantly in composition, suggesting diff erent sources. Eleven samples of white glass original to the window are identical within analytical error, suggesting they came from the same batch, but the head of Christ is from another panel. Blue and flashed red glass were each the product of more than one batch of melting. Primarily, the condition of the glass is dependent upon silica content. Further investigations of other panels from the Great East Window, and of other windows by Thornton, are ongoing

Problematyka badań witraży średniowiecznych

Na podstawie badań ponad 900 fragmentów średniowiecznych szkieł witrażowych, pochodzących z różnych miejsc i okresów (od XII do XVIw.), omówionych zostało kilka wybranych zagadnień związanych z metodyką badawczą i interpretacją wyników. Poruszona problematyka dotyczy dziewiętnastowiecznej restauracji witraży i ich współczesnej interpretacji, badań pojedynczej kwatery, okna i zespołu okien oraz szkieł barwnych. W ostatnim przypadku, dokładniej zostały omówione szkła czerwone oraz dwunastowieczne szkła niebieskie, wytwarzane przy użyciu rzymskich tesserae. / Research on more than 900 fragments of medieval stained glass from different places and periods (from the 12th to the 16th c.) gives grounds for a discussion of select issues connected with research methodology and interpretation of results. Topical issues concern 19th c. restoration of stained glass windows and their modern interpretation, research on particular panels, windows and sets of windows, as well as coloured glass, in the lattermost case especially red glass and 12th c. blue glass produced from Roman tesserae

Regional patterns in medieval European glass composition as a provenancing tool

A legacy dataset of 1329 major element analyses of medieval glass (12th-15th centuries) has been compiled and analysed for geographical distribution of compositional characteristics. Three regional compositional types may be distinguished using simple elemental plots, associated with glass production in northwestern France, in the region around the Rhine, and in central Europe. Distribution maps are presented to aid interpretation and use of the data. The application of the approach is illustrated through three case studies. Late thirteenth-early fourteenth century medieval stained glass from York Minster (n = 91), late fourteenth-century stained glass from New College Oxford (n = 79) and a single medieval mirror found in Egypt were analysed using scanning electron microscopy–energy dispersive analysis. The York coloured and white glasses were identical and consistent with an origin in NW France. In the late fourteenth century, the coloured glass samples from Oxford were from the Rhenish region, while the white glass is consistent with an origin in NW France or England. The mirror glass from Egypt is of central European origin, and similar mirror glass is known from Italy. The apparent dominance of German mirror production may reflect an advantage of the glass, which is low in iron. The meta-analysis of the legacy data shows significant potential for developing an understanding of the production and movement of medieval glass