The first early Christian churches used mosaic for decorative and iconographic designs. In Ravenna, during the 5th and 6th centuries, the process of mosaic evolved to become Byzantine mosaic, for it was very widespread in Byzantium. The Muslims greatly exploited this art to decorate their Mosques and palaces. At the end of the Middle Ages, the fancy for mosaic faded, though it could still be found in Italian churches. Mosaic came back only during the 20th century thanks to the art deco style. Artists like Klimt, Gaudi and Chagall brought full value back to it. Today, many artists still carry on this art and use various techniques and materials.