Stained glass, an art form that has developed over more than 1000 years, continues to compel art lovers, historians and devout believers in equal measure. The public has come to appreciate innovative new developments even as it is more keenly aware of obligations to study and protect historic sites and their essential decorative programmes. periods in which stained glass has emerged as a notable art form through examining the methods by which it was produced, and the origins, symbolism and contexts in which it is displayed.