184 ceramics and pottery: Rome Amphora from Pompeii, Italy (© The Trustees of the British Museum) directly related to their function as transport containers In order to function effectively as containers for food, amphorae also needed to be watertight, thick, strong enough to withstand the stresses of maritime shipping, and large enough to contain between and 10 gallons of liquid It was also necessary to produce amphorae in standardized sizes and shapes, so that large numbers of them (often up to 3,000) could be loaded efficiently into the cargo holds of ships The production of amphorae therefore presented a significant technological challenge For this reason, amphorae were usually made in specialist workshops located near the harbors from which trade goods were shipped Potters in each region developed specific clay “recipes” based on their understanding of the relative strengths of different clays and mineral additives Assembly-line techniques were also employed, with one craftsman producing the top half of a vessel, another producing the lower half, and another joining the halves and adding handles and so on Amphorae are very important indicators of trade patterns and other economic structures The presence of a Spanish olive oil container on a small farmstead in Jordan, for example, or the discovery of a North African wine jar in a fortress in Britain says a great deal about the extent of trade, the movement of goods, and the consumption of food within disparate provincial populations The Romans employed several specialized ceramic vessels for cooking Roman cooks, like modern chefs, could choose from a wide variety of pots and pans designed to optimize the success of different cooking techniques Herbs, vegetables, and soft cheeses were ground and mixed in the mortarium, a heavy bowl with sharp stone fragments embedded in its interior surface The olla (or aula) was a deep, round-bottomed vessel used for boiling stews or porridge One could fry or sauté fish in a shallow-angled pan with a nonstick surface (patera or patina) whereas the patella, a deep, straight-sided pan, was most suitable for baking casseroles (which were much-loved and characteristically Roman dishes) Grills for cooking meat were also regularly made from clay, as was the clibanus, a portable oven for bread baking These vessels, in various sizes, made up a standard “set” found in most Roman households across the empire Beyond the standard cookware repertoire, cooks throughout Italy and the provinces also owned other vessels that reflected regional preferences in food preparation Archaeological analysis of how cookware sets vary provides important information about Roman food preferences across the empire Casseroles, for example, are found in relatively small quantities in provinces without a strong Roman colonial presence, as the dish is used for a specialized form of cooking most popular in Italy itself that only rather slowly became popular in other parts of the Mediterranean Most cookware was produced in local workshops, and only a small number of ceramic cooking vessels were exported beyond regional markets While metal versions of these objects were available, they were more expensive than the standard ceramic vessels and are less commonly found Tableware includes all vessels intended for food service and dining, from pitchers and platters to small cups and plates Many Roman tableware vessels were decorated with bright red slip and intricate designs in raised relief These designs consisted of simple geometric patterns; images of fish, birds, and plants; early Christian iconography, or symbols and images; elaborate mythological scenes; and workshop trademarks Vessels decorated in this style are often referred to as terra sigillata Terra sigillata vessels were first produced in Italy in the first century b.c.e Unlike amphorae and cookware, which were thrown by hand on a potter’s wheel, terra sigillata objects were made in molds in large factories Clay molds were created in the desired shape, and decorative patterns were cut into the interior of the molds When the molds were complete, they could be used to make hundreds of standardized cups, bowls, plates, and platters very rapidly Soft, wet clay was pressed firmly into a mold and smoothed so that the exterior of the finished vessel would exhibit the desired pattern in raised relief Once the clay was dry, the vessel was removed from the mold, coated with red slip, and finished with a decorative base and handle while the mold was immediately used