Light, Vision, and Architecture.

There is an intimate relation between architecture and its decoration. Whereas in early Christian and early medieval churches mosaics and paintings on walls had been the primary medium for the presentation of sacred stories, the elimination of solid mural surfaces and the transformation of the Gothic building into a skeletal frame led to the ascendancy of stained glass during the twelfth century. No doubt, the importance of an aesthetic that emphasized light as a metaphor of the Divine and spiritual experience spurred the creation of an architectural system that made a maximum expanse of stained glass possible. A third factor to consider is the rise of interest, during the twelfth century, in vision and optics. Not only were scholars curious about how physical objects and visual phenomena—rocks or rainbows—were seen...