Stained glass is used to express both the structure created by the combination of colored glass and the art of making it. It is known as revzen or elvan window in mosques. Although stained glass is generally made by soldering colored glass pieces together with lead filling material, painted glass and brass colored joining material can also be used to enrich the design. The art of stained glass requires not only artistic skill and creativity in its visual aspect, but also good engineering calculations to ensure that these decorative pieces can stand firmly on large surfaces. Stained glass is a product of the development of the art of glass ornamentation used since ancient times. The earliest examples of stained glass were found in the 9th century. The art of glass decoration was especially developed by the Eastern Mediterranean civilizations. In Anatolia, stained glass examples are found during the Seljuk and Ottoman Empire periods. They generally used decorations made of translucent and semi-transparent colored glass in mosques, tombs, palaces and mansions. In Islamic art, the revzen is much simpler than in European art. Glass pieces do not always have to be colored and plaster is used as a binding element. Rather than figurative patterns, the decorations of the revzen mostly include flowers, plants and geometric shapes. Intensely decorated revzens are also called revzen-i menkuş.