furnace and the Last Supper. In one remarkable mural, in the Catacomb of the Aurelii, is the earliest image of Jesus, as he came to be commonly depicted, as a bearded, Jewish man in long robes. In this particular image he is preaching, not to a group of people but to a flock of sheep and goats, representing the faithful and the wayward. Mural painting was to become a common form of enlightening decoration in Christian churches. Biblical themes rendered in mural can be found all over the Christian world. They are a more common form of church decoration in some regions than others. Painted churches are common throughout those areas where the Eastern Orthodox Church prevails. In Romania there is an unusual group of churches in which it is the exterior rather than the interior which is richly decorated, the large arcaded porches containing images of the Last Judgement. Mural painting was also common in Italy, where the method employed was generally fresco, painting on freshly laid, slightly damp plaster. Many fine examples have survived from the Medieval and Early Renaissance periods. Remarkably, the best known example of such Biblical story-telling was not created for the edification of the poor but for the rich and powerful, the Ceiling of the Sistine Chapel created by Michelangelo for Pope Julius II. Murals occur in France, particularly in the south where the walls tend to be wider, rather than the north where the art of stained glass prevailed. In England, few examples survived the depredations of the Reformation. Some fine Early Medieval examples exist in Germany and Spain. Mosaic Mosaic is the art of decorating solid surfaces with pieces of multi-coloured stone or glass set in mortar. Golden mosaic can be created by applying gold leaf to a single surface of a transparent glass tile, and placing the gilt inwards towards the mortar so that it is visible but cannot be scraped. The gilt tiles are often used as a background to figures, giving a glowing and sumptuous effect. Mosaic can be applied equally well to flat or curved surfaces and is often used to decorate vaults and domes. In churches where mosaic is applied extensively, it gives an impression that the interior of the church has been spread with a blanket of pictures and patterns. Mosaic was a common form of decoration throughout the Roman Empire and because of its durability