mould was therefore decorated on its interior surface with a full decorative design of impressed, intaglio (hollowed) motifs that would appear in low relief on any bowl formed in it. As the bowl dried, the shrinkage was sufficient for it to be withdrawn from the mould, in order to carry out any finishing work, which might include the addition of foot-rings, the shaping and finishing of rims, and in all cases the application of the slip. Barbotine and appliqué ('sprigged') techniques were sometimes used to decorate vessels of closed forms. Study of the characteristic decorative motifs, combined in some cases with name-stamps of workshops incorporated into the decoration, and also sometimes with the cursive signatures of mouldmakers, makes it possible to build up a very detailed knowledge of the industry. Careful observation of form and fabric is therefore usually enough for an archaeologist experienced in the study of sigillata to date and identify a broken sherd: a potter's stamp or moulded decoration provides even more precise evidence. The classic guide by Oswald and Pryce, published in 1920 set out many of the principles, but the literature on the subject goes back into the 19th century, and is now extremely voluminous, including many monographs on specific regions, as well as excavation reports on important sites that have produced significant assemblages of sigillata wares, and articles in learned journals, some of which are dedicated to Roman pottery studies. The motifs and designs on the relief-decorated wares echo the general traditions of Graeco-Roman decorative arts, with depictions of deities, references to myths and legends, and popular themes such as hunting and erotic scenes. Individual figure-types, like the vessel-shapes, have been classified, and in many cases they may be linked with specific potters or workshops. Some of the decoration relates to contemporary architectural ornament, with egg-and-tongue (ovolo) mouldings, acanthus and vine scrolls and the like. While the decoration of Arretine ware is often highly naturalistic in style, and is closely comparable with silver tableware of the same period, the designs on the Gaulish products, made by provincial artisans adopting Classical subjects, are intriguing for their expression of 'romanisation', the fusion of Classical and native cultural and artistic traditions. Many of the Gaulish manufacturing sites have been extensively excavated and studied. At La Graufesenque in southern Gaul, documentary evidence in the form of lists or tallies apparently fired with single kiln-loads, giving potters' names and