Despite its great age, this 13th-century panel not only still has most of its original medieval glass, but also most of its original lead. The rough surface of the lead, cast in moulds, has been planed, giving it a distinctive facetted appearance. The glass is unpainted and therefore relies on the pattern of the leads for its decorative effect.
The clear glass is lightly tinted as a result of the impurities in the raw materials that were used to make it. This kind of simple glazing, known as grisaille, is often associated with Cistercian churches, in which it expressed the simplicity of the Cistercian monastic ideal. It was also popular wherever a higher level of light or a cheaper form of glazing was requested.