Pasiteles was an artist of great versatility and scientific attainments. He wrote a work on Greek art in five books, which served as a primary authority for Pliny.[107] He was a goldsmith and a metal worker, and his range of sculptural subjects was very wide. He is known to have paid special attention to the sculpture of animals, and it is recorded that he studied a lion from life at the Roman docks. He seems also to have been the originator of a device, which did much to injure the later development of marble sculpture.[108] Bronze workers had always had to prepare clay models usually finished in wax after the invention of the _cire perdue_ process; metal workers of all kinds had need of the same preparation; but in marble sculpture the use of models had hitherto been confined to pedimental designs or similar productions prepared by great artists and worked out by masons. The effect on architectural sculpture had usually been unfortunate. It is expressly told us of Pasiteles that he always made use of clay models for all his work, that is, including his marble sculpture. It was, no doubt, inevitable in a commercial age, where copies were in great request, and where several replicas were made of the one original, that the use of clay models designed by the master and copied in marble by pupils and workmen should become general. The ultimate results of such a procedure were destructive to the whole art; for workshops came to possess a stock of models and to turn out machine-made copies on demand. The finished statue became merely the work of masons untouched by the original master, who devoted himself entirely to the preparation of models and designs. The sculptor’s workshop instead of being a studio degenerated into a factory. No doubt Pasiteles himself was an artist who did much original work, but in the hands of his pupils and followers statue-making was a mere trade. Unfortunately the works of his school, which survive for us, are almost wholly these mechanical and commercial by-products. The works of real fancy and charm have almost wholly disappeared. Many of the Hellenistic reliefs, especially those of the Palazzo Spada type, are to be attributed to the Greek sculptors in Rome. These show an elegance and a dainty affectation quite in keeping with the spirit of the age. The group of Appiades (Fig. 51) by Stephanos,[109] a pupil of Pasiteles, has been recognized in the group of three nude girls holding up a water-pot, now in the Louvre.[110] The Three Graces are also a conception of this age. Neat competent work of a decorative type seems to sum up the original achievements of this school, which fall more or less in line with the Neo-Attic reliefs shortly to be considered.