Coloured glass used to make decorative windows and other objects through which light passes. Stained glass is often made in large, richly detailed panels that are set together in a framework of lead. Like all coloured glass, it acquires its colour by the addition of metallic oxides to molten glass. A purely Western phenomenon, stained glass originated as a fine art of the Christian church, beginning in the 12th–13th century, when it was combined with Gothic architecture to create brilliant, moving effects. A decline set in after the 13th century, when stained-glass artists began to seek the realistic effects sought by Renaissance painters, effects to which the technique was less suited and which diverted artists from exploiting the all-important light-refracting quality of glass. More recently, stained-glass artists have again achieved high quality: during the 19th-century Gothic revival, in the Art Nouveau designs of Louis Comfort Tiffany, and in the work of such 20th-century artists as Marc Chagall.