The origins of the first stained glass windows are lost in history. The technique probably came from jewelry making, cloisonné and mosaics. Stained glass windows as we know them, seemed to arise when substantial church building began. By the 10th century, depictions of Christ and biblical scenes were found in French and German churches and decorative designs found in England.There is a mystery to glass: It is a form of matter with gas, liquid and solid state properties. Glass is most like a super-cooled liquid. It captures light and glows from within. It is a jewel like substance made from the most ordinary materials: sand transformed by fire. Before recorded history, man learned to make glass and color it by adding metallic salts and oxides. These minerals within the glass capture specific portions from the spectrum of white light allowing the human eye to see various colors. Gold produces stunning cranberry; cobalt makes blues; silver creates shades of yellow and gold while copper makes greens and brick red.
Techniques of stained glass window construction were described by the monk Theophilus who wrote a how to for craftsmen about 1100 AD. It describes methods little changed over 900 years: “if you want to assemble simple windows, first mark out the dimensions of their length and breadth on a wooden board, then draw scroll work or anything else that pleases you, and select colors that are to be put in. Cut the glass and fit the pieces together with the grozing iron. Enclose them with lead cames… and solder on both sides. Surround it with a wooden frame strengthened with mails and set it up in the place where you wish.”