Pottey and Stone in the evaluation of ancient trade

Introduction

This article briefly compares and contrasts pottery and stone as two different means of evaluating ancient trade. The paper is divided in 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 used to be traded and travelled around, either as plain natural resources to be used in production, or as finished products for potential consumers. Trade activities required short or long distance travelling, usually between the selection areas of certain natural resources, or 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, which is the soil and its different 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 their clay. 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 in solid pieces, such as stones, or granulate by weathering, forming small and fine sediments of clay. Due to their original similarities, the examination techniques employed for both materials are exactly the same, 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 through any of the above techniques, they can be paralleled with geological maps or existing geological samples. The comparison can suggest their source of 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 the identification of the distribution areas, where such materials circulate, either 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 define their distribution scale, which can range between random and systematic. If such distribution repeats frequently, it is likely to associate 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 other cases, inscriptions or stamps on pottery may suggest long distance trade, while in other cases, textual or historical sources are likely to confirm a specific trade route. For example, workshop stamps on Arretine pottery from the 1st century BC, which have been recovered in central and north Europe, indicated a centralised production in North Italy, which circulated such pottery 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 ones that can travel around. Budden (2008) has demonstrated that craftsmanship can also travel around, which could be in the form of people, technological information, craft knowledge or transferable manufacture skills. The study of distribution areas can assist in evaluating trade; however, one needs to be first sure that such distribution is the result of trade.

Pottery in ancient trade

In antiquity, pottery circulated in three different ways: firstly, as plain clay, a natural resource, which was transported to different production centres; secondly, as ceramic vessels, which were sold to different markets and consumers; and thirdly, as ceramic containers transporting other traded commodities. In archaeology, such forms of trade bear similarities and differences, which cannot be thoroughly explained in this short study; therefore, the following paragraphs will only offer 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, sometimes it may be the result of direct or indirect contacts 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 lithis is relatively easier compared to pottery. A good example is obsidian trade in 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, which was either sold in the open market or was exchanged for other goods or services. The study of pottery as a traded commodity is complicated due to the fact that ceramic vessels reflect multiple production modes and serve multiple functions. Peacock (1982), for example, uses ethnological evidence from the Balkans to suggest that pottery made at household production level is often sold at the open market for additional income. In other cases, small or large ceramic industries, which employ skilful potters and use advanced production technologies, tend to produce finer vessels traded at expensive 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’ finewares is the Roman world was not only due to their functional qualities, but also due to their symbolic content: such vessels 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 finewares were traded in more expensive prices compared to common coarsewares due to their symbolic function, which served the socio-ideological pursues 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 social status, which might have existed in the past. Apart form 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 in ancient trade is through the study of pottery that was once 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 different 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), which was discovered in 1982 at Kaș, at the South-Eastern coasts 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, the ship stopped in Cyprus to receive local amphorae with agricultural products, which were probably meant to be transported 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 natural resource or finished product. Unlike pottery, stone vessels could not serve as containers to transport other commodities due to their weight and manufacture complexities. 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 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 such materials from specific cultural groups or the production of lithic artefacts made of specific stone types (Brothwell 1983, 10). One of the most easily identifiable stones in Neolithic and Bronze Age Aegean, which was traded across long distances, was obsidian. Trace element analyses have shown that obsidian, which was once extracted at the island of Giali to the North of Rhodes, was often transported to Minoan Crete and was used for the production of 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 did not only access local marbles from Mount Hymettous and Mount Pentelikon, but also imported marbles from the islands Skyros, Delos, Thassos and Lesbos. They even imported precious rosso antico marble from Laconia, which was the land of their main enemies, the Spartans (Kempe, 1983a). By using such variety of imported marbles, the Athenians probably wished to stress their city-state’s propaganda: accessing 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 century AD there used to be an organised mining system, which brought different qualities of marble to Rome. Marble was primarily used in public buildings, which were meant to promote state propaganda. Expensive marbles were also used in private residences in order to projected social status and wealth. Mineral analyses have shown that such marbles came from different parts of the Roman Empire, such us the Greek islands, 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 ancient stone trade, certain stone types, which contained native precious minerals (e.g. gold, silver, platinum and palladium) had high commercial values. 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).

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 distanced markets. Good quality products made of volcanic leucitophyre from the Orvieto region were traded by the Romans all across 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, instead, they imported better quality millstones from Orvieto, which was far 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 was to receive a heavier cargo from another port along its voyage, the crew would then loosen the ballast ashore and replace its weight with more cargo. Nowadays, archaeologists identify such stone deposits ashore, mostly in the vicinity of 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 stones of volcanic origins, such as basalts, are easier to identify and pinpoint a specific location with such rocks. Furthermore, ballast, which was once left ashore by ships, was sometimes collected by the local communities and was used in constructions. For example, many granitic stones found in the buildings of La Rochelle in France, originally came from Canada. These used to be ballast of large merchant ships crossing the Atlantic and were dumped ashore when such ships came closer to their final destination port. Due to their quality, the stones were re-used 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 role in the reconstruction of ancient trade. Both materials are studied through either microscopic or quantitative methods.

More specifically, pottery and stone consist of rock forming minerals, the geological origin of which can be determined by various analytical techniques (e.g. petrology). Furthermore, quantification studies can determine artefact distribution; therefore, the possibility of frequent trade or other form of organised exchange, as opposed to random contacts. Quantification is connected to typological studies, which define the functionality of various artefacts; however, the study of ancient trade on the basic of pure typology can often be problematic due to artefact re-use.

Pottery and stone have been both 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 suggests 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 of functional commodities (as in practically functional); it can also suggest trade of 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 compared to other traded commodities made of pottery or worked stone.

The main difference between pottery and stone in relation to trade is that the former could produce containers for transporting other traded products. By contrast, stone containers were rare and impractical when it came to transporting goods. The study of large ceramic containers often informs on the origin of the traded merchandise; however, archaeologists should bear in mind that such ceramic containers might have often been reused. Such reuse is likely to suggest that pottery might have had secondary or even multiple functions, which might not have necessarily related 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 assists in the reconstruction of ancient trade routes, particularly in maritime archaeology.

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