ceilings, and inside and outside walls that were going to get wet. The famous copy of a Hellenistic painting in the Alexander Mosaic in Naples was originally placed in a floor in Pompeii; this is much higher quality work than most Roman mosaic, though very fine panels, often of still life subjects in small or micromosaic tesserae have also survived. The Romans distinguished between normal opus tessellatum with tesserae mostly over 4 mm across, which was laid down on site, and finer opus vermiculatum for small panels, which is thought to have been produced offsite in a workshop, and brought to the site as a finished panel. The latter was a Hellenistic genre which is found in Italy between about 100 BC and 100 AD. Most signed mosaics have Greek names, suggesting the artists remained mostly Greek, though probably often slaves trained up in workshops. The late 2nd century BC Nile mosaic of Palestrina is a very large example of the popular genre of Nilotic landscape, while the 4th century Gladiator Mosaic in Rome shows several large figures in combat. Orpheus mosaics, often very large, were another favourite subject for villas, with several ferocious animals tamed by Orpheus's playing music. In the transition to Byzantine art, hunting scenes tended to take over large animal scenes. Metalwork Metalwork was highly developed, and clearly an essential part of the homes of the rich, who dined off silver, while often drinking from glass, and had elaborate cast fittings on their furniture, jewellery, and small figurines. A number of important hoards found in the last 200 years, mostly from the more violent edges of the late empire, have given us a much clearer idea of Roman silver plate. The Mildenhall Treasure and Hoxne Hoard are both from East Anglia in England. There are few survivals of upmarket ancient Roman furniture, but these show refined and elegant design and execution. Coins and medals Few Roman coins reach the artistic peaks of the best Greek coins, but they survive in vast numbers and their iconography and inscriptions form a crucial source for the study of Roman history, and the development of imperial iconography, as well as containing many fine examples of portraiture. They penetrated to the rural population of the whole Empire and beyond, with barbarians on the fringes of the Empire making their own copies. In the Empire medallions in precious metals began to be