Detail from previous photo: chalice roundel
"In 1134 the ascetic Cistercian order had
forbidden in its own churches the use of coloured or figured glass ... Not only was
it cheaper but it also let in more light. Such glass was mainly white, thinly painted
in outline with black foliage patterns. Sometimes spots of coloured glass were added
to give variety ... This type of glass was known as 'grisaille.'