The history of stained glass stretches back, like an increasingly brilliant hall, to the 11th century. There it shatters into fragments and disappears. Historians now only guess that the art developed first in the Middle East, as an offshoot of mosaic making, since stained-glass windows are nothing but translucent mosaics held together by lead.
In the Middle Ages, the very faith of Europe came to life in the cathedrals' stained-glass windows. The artists who made them were revered, but most of their names are forgotten. The art reached its highest level in France, and France's earliest known fragment is a "Head of...