Pottery and Stone in the evaluation of ancient trade

Introduction

This article briefly compares and contrasts pottery and stone as two methods for evaluating ancient trade. The paper is divided into four sections. The first section explains how the study of pottery and stone, worked or unworked, can provide information on ancient trade. The second section discusses the role of pottery in ancient trade and presents specific examples. The third section discusses the role of lithics in ancient trade and presents examples of traded worked or unworked stone. The final section concludes on the contribution of these two types of materials in evaluating ancient trade and summarises their similarities and differences.

The study of pottery and stone in the evaluation of ancient trade

Backed clay and stone were two popular materials used in the production of material culture in past societies. Such materials were traded and transported, either as raw materials for production or as finished products for potential consumers. Trade activities required short- or long-distance travel, usually between the areas where certain natural resources were selected, the production areas of certain finished commodities, and the areas of their distribution (Rice 2005; Orton et al. 1993; Sinopoli 1991; Renfrew and Bahn 1991). The distribution areas could have been big open markets established specifically for trade, small local markets along main transport routes, or even the households of individual consumers (Peacock 1982; Renfrew 1977). In modern archaeology, the study of pottery and stone can help to evaluate trade in two basic ways: firstly, by identifying the original sources of natural materials or finished products; secondly, by mapping the distribution of such materials in relation to their quantities and areas of recovery (Rice 2005; Orton et al. 1993; Sinopoli 1991; Brothwell, 1983).

Technically, pottery and stone derive from the same natural source: soil and its various mineral components. Artefacts made of worked stone vary according to the type of stone originally selected for their production; backed-clay products, such as pottery, vary according to the geological composition of the clay used. Both materials consist of rock-forming minerals, such as silicates, micas, quartz, feldspars and others, which derive from larger parent rocks. They either break down into solid pieces, such as stones, or granulate through weathering, forming fine clay sediments. Given their original similarities, the examination techniques used for both materials are identical, based on the identification of their mineral components. Such techniques include Thin-Section Microscopy, Heavy Mineral Analysis, X-Ray Diffraction, X-Ray Fluorescence, Scanning Electron Microscopy, Optical Emission Spectroscopy, Atomic Absorption Spectroscopy, Neutron Activation Analysis and others. After these mineral inclusions have been identified using any of the above techniques, they can be matched to geological maps or existing geological samples. The comparison can suggest their origin, which is likely to coincide with the location of their original selection, extraction, or production (Rice 2005; Sinopoli 1991; Kempe and Templeman 1983; Williams 1983).

The second step in evaluating trade is identifying the distribution areas where such materials circulate, whether as traded natural resources or finished commodities. The most common way of mapping such distributions is after recovering pottery or stone through land surveying or excavation. After the recovery of such artefacts, quantification methods are used to determine their distribution scale, which can range from random to systematic. If such a distribution repeats frequently, it is likely to be associated with a specific production centre (Orton et al. 1993; Sinopoli 1991; Renfrew and Bahn 1991; Peacock 1982).

Studying distribution areas can sometimes be problematic, particularly when seeking to uncover trade routes. The study of artefact typologies may not always verify the distribution of traded commodities; instead, local artefact types, which could imitate forms from other production centres, are likely to circulate in large quantities in regional markets. Instead of typological analysis, petrological identifications can be more accurate in determining artefact provenance. In some cases, inscriptions or stamps on pottery may suggest long-distance trade, while in others, textual or historical sources are likely to confirm a specific trade route. For example, workshop stamps on Arretine pottery from the 1st century BC, recovered in central and northern Europe, indicate a centralised production in Northern Italy, with this pottery circulating many miles away through an organised trade network (Peacock 1982; Johns 1971; Brown 1968).

Whatever the case, one needs to be careful with such interpretations, as products are not the only things that can travel. Budden (2008) has demonstrated that craftsmanship can also travel, in the form of people, technological information, craft knowledge, or transferable manufacturing skills. The study of distribution areas can assist in evaluating trade; however, one must first be sure that such distribution is the result of trade.

Pottery in ancient trade

In antiquity, pottery circulated in three ways: firstly, as plain clay, a natural resource, transported to different production centres; secondly, as ceramic vessels, sold to different markets and consumers; and thirdly, as ceramic containers for other traded commodities. In archaeology, such forms of trade exhibit both similarities and differences that cannot be fully explained in this short study; therefore, the following paragraphs will offer only a brief overview.

The study of traded natural resources is problematic, particularly clay, which leaves no visible trace in the archaeological record. With this in mind, the transportation of clay from one location to another may not always suggest direct trade. Still, it may sometimes result from direct or indirect contact and exchange. Most studies on clay resources are based on ethnoarchaeological observations, which suggest that potters can travel long distances to access suitable clays for their workshops (Rice 2005; Sinopoli 1991; Peacock 1982; Renfrew 1977). Access to fine-quality clays is not always possible, particularly when such clay sources are located in areas under foreign rule. Exchange of goods or other commercial agreements may allow clay trade; however, such transactions leave no visible trace in the archaeological record. Certain characteristics of the original clay can be identified in the final product through petrological analysis; however, provenance may not always be possible due to the geological similarities of different clays. By contrast, the provenance of lithics is relatively easier than that of pottery. A good example is the obsidian trade in the Ancient Aegean: obsidian is easily identifiable, and due to its distribution, it is nowadays clear that it was moved around quite frequently, either as a natural resource, as a semi-processed material, or even as a finished product (Brothwell, 1983, 15).

In the archaeological record, pottery most commonly represents a functional commodity, sold in the open market or exchanged for other goods or services. The study of pottery as a traded commodity is complicated because ceramic vessels reflect multiple production modes and serve multiple functions. Peacock (1982), for example, uses ethnographic evidence from the Balkans to suggest that household-produced pottery is often sold in the open market for additional income. In other cases, small or large ceramic industries that employ skilled potters and use advanced production technologies tend to produce finer vessels sold at high prices. In the Roman world, the peak of such fineware trade was between the 1st and 3rd century AD, when ‘Samian’ pottery was widely distributed in the Central and Northern European territories of the Roman Empire (Peacock 1982; Brown 1968; Johns 1971). The popularity of ‘Samian’ fineware in the Roman world was not only due to its functional qualities but also to its symbolic content: such vessels were used to reflect social status and wealth, marking the consumption habits of the Roman elites. The relationship between status ceramics and acquisition cost is not always clear due to the lack of evidence. It is likely that fineware was traded at higher prices than common coarsewares due to its symbolic function, which served the socio-ideological pursuits of the Roman elites (Rice 2005; Sinopoli 1991; Skibo 1992). Again, the study of archaeological ceramics may not always reveal the relationship between vessel quality, traded cost, and past social status. Apart from ceramic finewares, social status and wealth might have been projected through other household artefacts, such as vessels made of glass, copper, silver or even gold (e.g. Vickers and Gill 1994).

The clearest picture of ancient trade comes from the study of pottery used to transport other traded goods. For example, 1st-century BC Roman amphorae from Cosa in Northern Italy, which carried the stamps of the potter Sestius, have been recovered in various Central European locations, indicating long-distance wine trade (Sinopoli 1991, 114). Excavated shipwrecks carry amphorae typologies tied to different production centres, suggesting long-distance naval trade. A typical example is the Late Bronze Age Uluburun shipwreck (14th century BC), discovered in 1982 at Kaș on the South-Eastern coast of Turkey (Welter-Schultes 2007). The typological analysis of its cargo showed that the ship had departed from Syria, loaded with local Syro-Palestinian and Egyptian luxuries; however, it stopped in Cyprus to receive local amphorae containing agricultural products, which were probably intended for transport to the North-West (Renfrew and Bahn 1991, 328-329).

The Uluburun shipwreck shows that typological studies on ancient ceramic vessels are likely to reveal ancient trade routes. Typological studies suggest that local or regional ceramic vessel forms were once used to transport goods produced in the same area. In other words, the origin of the traded merchandise is determined by the typological origin of its container. This particular approach can sometimes present certain challenges. For example, archaeological ceramics recovered from certain locations may not always relate to their primary function. They are likely to associate with secondary or even multiple functions, which may not always reflect ancient trade (Skibo 1992; Sinopoli 1991).

Stone in ancient trade

As with pottery, stone was traded either as a raw material or as a finished product. Unlike pottery, stone vessels could not serve as containers for other commodities due to their weight and the complexity of their manufacture. In general, stone was involved in ancient trade in three ways: firstly, as raw material, which was transported to other locations in order to be used in local craft production; secondly, as a finished artefact, which was traded in some kind of market; and finally, as sailable ballast for cargo ships, which transferred other traded commodities.

In the archaeological record, unprocessed or semi-processed stones of non-local geological origins are likely to indicate stone trade. Such stones are normally recovered in large quantities, and their distribution is likely to suggest either the exploitation of these materials by specific cultural groups or the production of lithic artefacts made from specific stone types (Brothwell 1983, 10). One of the most easily identifiable stones in the Neolithic and Bronze Age Aegean, traded over long distances, was obsidian. Trace element analyses have shown that obsidian, once extracted on the island of Giali to the North of Rhodes, was often transported to Minoan Crete and used to produce elaborate elite artefacts (Cann 1983; Renfrew et al. 1965).

Another example of extensive stone trade in antiquity was marble. For the construction of the Parthenon during the 5th century BC, the Athenians not only accessed local marbles from Mount Hymettus and Mount Pentelikon, but also imported marbles from the islands Skyros, Delos, Thassos and Lesbos. They even imported precious Rosso Antico marble from Laconia, the land of their main enemies, the Spartans (Kempe, 1983a). By using such a variety of imported marbles, the Athenians probably sought to emphasise their city-state’s propaganda: the use of expensive or exotic resources symbolised Athens’ economic power and prosperity, which was partly due to organised trade.

A similar form of marble trade existed in the Roman world. During the 1st and 2nd centuries AD, an organised mining system brought different grades of marble to Rome. Marble was primarily used in public buildings intended to promote state propaganda. Expensive marbles were also used in private residences in order to project social status and wealth. Mineral analyses have shown that such marbles originated from different parts of the Roman Empire, including the Greek islands and the modern coasts of Asia Minor and Egypt (Fant 1988; 1992). Polychrome marbles, in particular, were rare and most likely expensive; they were used for the construction of luxurious residences, such as Hadrian’s villa in Tivoli (Guidobaldy and Salvatori 1988; Salvatori et al. 1988).

In the ancient stone trade, certain stone types that contained native precious minerals (e.g., gold, silver, platinum, and palladium) had high commercial value. These were either acquired by the state or by wealthy patrons who wished to stress their elite social status and economic prosperity. Furthermore, the Roman elites used to purchase precious stones for the same reasons. Diamonds, corundum types (rubies and sapphires), beryl types (emeralds and aquamarines), topazes, zircons, garnets, green feldspars, and others were once targeted by Roman merchants, who travelled long distances to obtain them (Kempe, 1983b).

The stone trade did not only include unprocessed or semi-processed natural resources, but also finished products. In archaeology, such finds are described as lithic artefacts. The site of Nahal Lavan in Israel, for example, which dates to the Preceramic Neolithic B period, produced a series of obsidian arrowheads, blades, bladelets and other chips, the source of which was located at Gollu Dag in Central Anatolia (Yellin and Fractenberg 1992). Of course, this discovery may not necessarily describe ancient long-distance trade; however, the transportation of significant quantities of lithic artefacts across large distances is likely to imply some form of organised extraction, production and exchange network. The picture is perhaps clearer in European sites, where microscopic techniques have verified the origins of various prehistoric stone tools and have shown that such artefacts could travel far (Cummins 1983).

In the Roman world, millstones and quernstones were popular commodities sold in distant markets. Good-quality products made from volcanic leucitophyre from the Orvieto region were traded by the Romans throughout modern Italy. Millstones and quernstones from Orvieto have been found in Ostia, Pompeii, Herculaneum and Paestum. It is surprising that, although Pompeii, Herculaneum, and Paestum had access to similar volcanic stones from Mount Vesuvius, they instead imported better-quality millstones from Orvieto, which was far to the north (Peacock 1980).

The final use of stone in ancient trade was ballast in cargo ships. Ballast allowed ancient ships to float without tipping over when their cargo was not heavy enough to guarantee cruising stability. Ships that transported heavy cargoes, such as amphorae full of wine or olive oil, did not always need ballast to improve their sailing ability. When such heavy cargoes were left ashore or were replaced by lighter cargoes, the crew would counterbalance the ship’s original weight with ballast, which was mostly stones, sand and cobbles. If a ship were to receive heavier cargo from another port along its voyage, the crew would loosen the ballast ashore and replace it with the new cargo. Nowadays, archaeologists identify such stone deposits ashore, mostly near ancient ports. Petrological examinations determine the origin of such stones and are used to reconstruct part of the ship’s voyage (Peacock 1998).

The identification of the ballast’s origin is not always clear, as ancient ships often sailed along coastlines with similar geological formations. Rare volcanic rocks, such as basalts, are easier to identify and pinpoint a specific location. Furthermore, ballast, once left ashore by ships, was sometimes collected by local communities and used in construction. For example, many of the granitic stones used in the buildings of La Rochelle, France, originally came from Canada. These used to be ballast on large merchant ships crossing the Atlantic and were dumped ashore as they approached their final destination port. Due to their quality, the stones were reused in local buildings. In the same sense, ballast that was once dumped ashore could have been collected and sold in local markets as building material (Peacock 1998). The re-use or commercialisation of such stones suggests that studying trade routes through ballast can often be surprising.

Summary and conclusions

The evaluation of ancient trade is based on the reconstruction of commercial routes, which once connected different production centres and distribution areas. In archaeology, pottery and stone play crucial roles in reconstructing ancient trade. Both materials are studied through either microscopic or quantitative methods.

More specifically, pottery and stone consist of rock-forming minerals, the geological origins of which can be determined using various analytical techniques (e.g., petrology). Furthermore, quantification studies can determine artefact distribution; therefore, the possibility of frequent trade or other forms of organised exchange rather than random contacts. Quantification is closely linked to typological studies, which define the functionality of various artefacts; however, studying ancient trade solely through typology can be problematic due to artefact reuse.

Pottery and stone have been traded in the past, either as raw materials or as finished commodities. Trade activity may not always be identifiable, particularly when dealing with raw clay or unworked stones. By contrast, the distribution of processed or finished products, such as pottery, marble blocks, millstones or quernstones, is more likely to suggest trade activity, particularly if this can be cross-referenced with other analytical techniques.

The study of pottery and stone in the archaeological record may not only suggest trade in functional commodities (practically functional goods), but also in goods with specific symbolic content and social function. Such goods could have transmitted wealth, authority, or social status, while their acquisition cost could have been significantly higher than that of other traded commodities made of pottery or worked stone.

The main difference between pottery and stone in terms of trade is that pottery can produce containers for transporting other traded products. By contrast, stone containers were rare and impractical for transporting goods. The study of large ceramic containers often informs the origin of traded merchandise; however, archaeologists should bear in mind that such containers were often reused. Such reuse suggests that pottery may have had secondary or even multiple functions, unrelated to actual trade. Finally, plain stones were often used in naval trade as non-saleable (or sometimes saleable) ballast. The identification of their geological origin helps reconstruct ancient trade routes, particularly in maritime archaeology.

Bibliography

Brothwell, D., 1983, ‘Petrology and archaeology: an introduction’, in Kempe, D.R.C. and Harvey, A.P. (eds.) The Petrology of Archaeological Artefacts, Oxford: Clarendon Press.
Brown, A.C., 1968, Catalogue of Italian Terra Sigillata in the Ashmolean Museum, Oxford: Oxford University Press.
Sudden, S., 2008, ‘Skill amongst Sherds: Understanding the role of skill in the Early to Late Bronze Age in Hungary’, in Berg, I. (ed.) Breaking the Mould: Challenging the Past Through Pottery, Oxford: British Archaeological Review.
Cann, J.R., 1983, ‘Petrology of obsidian artefacts’, in Kempe, D.R.C. and Harvey, A.P. (eds.) The Petrology of Archaeological Artefacts, Oxford: Clarendon Press.
Cummings, W.A., 1983, ‘Petrology of stone axes and tools’, in Kempe, D.R.C. and Harvey, A.P. (eds.) The Petrology of Archaeological Artefacts, Oxford: Clarendon Press.
Fant, J.C., 1988, ‘The Roman emperors in the marble business: talists, middlemen or philanthropists?’, in Herz, N. and Waelkens, M. (eds.) Classical Marble: Geochemistry, Technology, Trade, Dordrecht, Boston, London: Kluwer Academic Publishers.
Fant, J.C., 1992, ‘The Roman imperial marble yards at Portus’, in Waelkens, M., Herz, N. and Moens, L. (eds.) Ancient Stones: Quarrying, Trade and Provenance, Leuven: Leuven University Press.
Guidobaldi, F. and Salvatori, A., 1988, ‘The introduction of polychrome
marbles in Late Republican Rome: The evidence from mosaic pavements with marble insertions’, in Herz, N. and Waelkens, M. (eds.) Classical Marble: Geochemistry, Technology, Trade, Dordrecht, Boston, London: Kluwer Academic Publishers.
Johns, C., 1971, Arretine and Samian Pottery, London: The Trustees of the British Museum.
Kempre, D.R.C., 1983a, ‘The petrology of building and sculptural stones’, in Kempe, D.R.C. and Harvey, A.P. (eds.) The Petrology of Archaeological Artefacts, Oxford: Clarendon Press.
Kempe, D.R.C., 1983b, ‘Raw materials and miscellaneous uses of stone’, in Kempe, D.R.C. and Harvey, A.P. (eds.) The Petrology of Archaeological Artefacts, Oxford: Clarendon Press.
Kempe, D.R.C. and Templeman, J.A., 1983, ‘Techniques’, in Kempe, D.R.C. and Harvey, A.P. (eds.) The Petrology of Archaeological Artefacts, Oxford: Clarendon Press.
Orton, C., Tyres, P. and Vince, A., 1993, Pottery in Archaeology, Cambridge: Cambridge University Press.
Peacock, D.P.S., 1980, ‘The Roman millstone trade: a petrological sketch’, World Archaeology (12), 43-53.
Peacock, D.P.S., 1982, Pottery in the Roman World, London and New York: Longman.
Peacock, D.P.S., 1998, The Archaeology of Stone: a report for English Heritage, London: English Heritage.
Renfrew, C., 1977, ‘Production and exchange in early state societies: The evidence of pottery’, Peacock, D.P.S. (ed.) Pottery and Early Commerce: Characterisation and Trade in Roman and Later Ceramics, London: Academic Press.
Renfrew, C. and Bahn, P., 1991, Archaeology: Theories, Methods and Practice, London: Thames and Hudson.
Renfrew, C., Cann, J.R. and Dixon, J.E., 1965. ‘Obsidian in the Aegean’, Annual of the British School in Athens (60), 225-47.
Rice, P.M., 2005, Pottery Analysis: A Sourcebook, Chicago and London: University of Chicago Press.
Salvatoru, A., Trucchi, D. and Guidobaldi, F., 1988, ‘The marbles used in
‘The decoration of Hadrian’s villa at Tivoli’, in Herz, N. and Waelkens, M. (eds.) Classical Marble: Geochemistry, Technology, Trade, Dordrecht, Boston, London: Kluwer Academic Publishers.
Sinopoli, C.M., 1991, Approaches to Archaeological Ceramics, New York: Plenum.
Skibo, J.M., 1992, Pottery Function: A Use-Alteration Perspective, New York and London: Premium Press.
Welter-Schultes, F.W., 2007, ‘Bronze Age shipwreck snails from Turkey: first direct evidence for oversea carriage of land snails in antiquity’, available at
http://mollus.oxfordjournals.org/cgi/contentiful1/74/1/79, accessed on 3/1/2009.
Vickers, M.J. and Gill, D.W.J., 1994, Artful Crafts: Ancient Greek Silverware and Pottery, Oxford: Clarendon Press.
Williams, D.F., 1983, ‘Petrology of Ceramics’, in Kempe, D.R.C. and Harvey, A.P. (eds.) The Petrology of Archaeological Artefacts, Oxford: Clarendon Press.
Yellin, J. and Fractenberg, F., 1992, ‘A re-examination of Nahal Lavan
obsidian’, in Waelkens, M., Herz, N. and Moens, L. (eds.), Ancient Stones: Quarrying, Trade and Provenance, Leuven: Leuven University Press.