backdrop to civil or military narrative scenes. This theory is defended by Franz Wickhoff, is debatable. It is possible to see evidence of Greek knowledge of landscape portrayal in Plato's Critias (107b–108b): ... and if we look at the portraiture of divine and of human bodies as executed by painters, in respect of the ease or difficulty with which they succeed in imitating their subjects in the opinion of onlookers, we shall notice in the first place that as regards the earth and mountains and rivers and woods and the whole of heaven, with the things that exist and move therein, we are content if a man is able to represent them with even a small degree of likeness ... Still life Roman still life subjects are often placed in illusionist niches or shelves and depict a variety of everyday objects including fruit, live and dead animals, seafood, and shells. Examples of the theme of the glass jar filled with water were skillfully painted and later served as models for the same subject often painted during the Renaissance and Baroque periods. Portraits Pliny complained of the declining state of Roman portrait art, "The painting of portraits which used to transmit through the ages the accurate likenesses of people, has entirely gone out ... Indolence has destroyed the arts." In Greece and Rome, wall painting was not considered as high art. The most prestigious form of art besides sculpture was panel painting, i.e. tempera or encaustic painting on wooden panels. Unfortunately, since wood is a perishable material, only a very few examples of such paintings have survived, namely the Severan Tondo from , a very routine official portrait from some provincial government office, and the well-known Fayum mummy portraits, all from Roman Egypt, and almost certainly not of the highest contemporary quality. The portraits were attached to burial mummies at the face, from which almost all have now been detached. They usually depict a single person, showing the head, or head and upper chest, viewed frontally. The background is always monochrome, sometimes with decorative elements. In terms of artistic tradition, the images clearly derive more from Greco-Roman traditions than Egyptian ones. They are remarkably realistic, though variable in artistic quality, and may indicate that similar art which was widespread elsewhere but did not survive. A few portraits painted on glass and medals from the later empire have survived, as have coin