An understanding of the manufacturing techniques and of the production sequence in terms of how pots are made provides us with an insight into the people making the ceramics. The clay, the raw material, is a plastic additive medium, allowing for traces of its manipulation by the potters, to be left in the finished ceramic product. Fashioning methods, or manufacturing techniques, used in creating a vessel are usually detectable. The traces are permanently embedded within a vessel once the firing stage is complete, meaning that the vessels carry information about the people making them, even if we study ceramics from consumption sites such as Portus.

According to academic ceramic literature, knowledge: ‘how we learn and do make things’ (Budden 2007) is socially and culturally based. It is therefore possible to look at technological variables in archaeological ceramics, the types of manufacturing techniques used for instance, to differentiate between archaeological communities. The Tripolitanian (Libyan) amphora handles, for example, are very distinctive. These are pulled and show characteristic finger indentation at the point where they attach the rim-neck or the shoulder in the case of the Tripolitana 2 type. Finger indentation is a characteristic noticed on most all of the Tripolitanian handles (Fig.1).

Different techniques used are indicative of societal aspects, such as organization of production. Having visited a number of traditional pottery workshops in Tunisia, it was apparent that the type of technique used was correlated to the type of pots being produced, to their size in particular, type of workshops, as well as the setting of the workshops, for instance urban versus more rural, and possibly to the relationships between workers (family businesses or more industrial), and finally the type of market which the pots were intended for.

Primary forming techniques can be categorized as being hand made or wheel thrown. However a mixture of techniques existed, and this is especially documented ethnographically in the making of large sized vessels. Coiling is one very common type of hand building. It indicates the creation of a ceramic vessel by adding sausages of clay.  However, coiling and shaping of coils on the wheel – wheel shaping – occurs in workshops in southern Tunisia, where they still manufacture large vessels resembling Roman amphorae. While wheel throwing is a very fast technique used for smaller vessels, wheel shaping is much more laborious and time-consuming, and it is used to make large to very large vessels.

Fashioning techniques can be observed macroscopically. Wheel thrown pots will show characteristic ridges or rilling, which tend to be symmetrical. These are particularly evident inside the vessels (Fig. 2). Instead,wheel-shaping shows rilling which tend to be blurred and also joins of coils (Fig. 3).

The production sequence for the manufacturing of amphorae includes a number of steps, from clay procurement, tempering of the clay with organic or inorganic inclusions, wedging (removing air and unwanted particles from) the clay, building up the ceramic body, adding additional features such as handles, the drying stage and firing.

The wedging of the clay, or preparation of the clay, is an important step, and much attention is given by the potters to such operation. Poor wedging can indeed leave air pockets in the clay, which could cause bubbles in the surface of vessel during the drying and firing stages, compromising the integrity of the vessel. And perhaps leading to the vessel exploding. This skilled and important step of the production sequence is traditionally done using hands or feet (Fig. 4).

Air pockets are particular evident in the Tripolitanian vessels at Portus (Fig. 5).

In terms of the manufacture of amphorae traded with Portus, they were wheel thrown or built up by a combination of coiling and wheel shaping. Working on the amphorae, different technological variables were noticed on Africana 1A and Tripolitanian vessels, two of the most traded vessels represented at Portus with the end 2^nd and beginning of the 3^rd centuries AD. The first was manufactured in Tunisia while the second was made in Libya. As I was interested in the forming techniques and in understanding the people behind their production, I started photographing the inside of the vessels and recorded a number of technological variables such as types of rilling, the presence or absence of joins of coiling, the degree of skill of execution in the preparation of the clay, and so on. The aim was to gain an insight, from the evidence, about how the different archaeological communities who invested a large amount of skill and labour in supplying Portus, were organized.

The Africana 1A amphora type according to vessel typology and fabric was mainly traded to Portus from Sullecthum, and a lesser amount from Leptiminus. These are both coastal town ports located in central Tunisia. The vessels show in most of the cases full wheel thrown rilling. Evidence of wheel throwing, is also visible microscopically within the micro fabrics, through means of petrological thin sections  (definition of fabrics and petrology are given in my previous blog). Indeed, the clay particles and the inclusions will assume a different orientation according to the manipulation of the raw material and the type of forming technique used. Syllecthum and Leptiminus fabrics show a sort of aligned orientation of the inclusions, which is associated with wheel throwing (Fig. 6, see also the petrological thin section of the Africana 1A in Sullecthum fabric in my previous blog post about ceramics).

Tripolitanian (Libyan) amphorae were built differently. A mixture of hand building and wheel throwing is visible, underlined by compression areas and finger imprints probably necessary to smooth the coils. Such characteristics are very apparent, for example on Tripolitanian vessels in Leptis Magna fabric (Fig. 7). In thin section, the inclusions of the Tripolitanian fabrics appear randomly distributed (Fig. 8). Also, a higher percentage of air pockets were noticed and recorded within the Tripolitanian amphorae (see Fig. 4).

What does this evidence or difference in the technology used suggest? Archaeological studies in North Africa show that the pottery workshops of Sullecthum and Leptiminus were located on the outskirts of the towns; these were semi-urban workshops. Evidence for olive oil production, such as standing olive oil presses, is, on the other hand, more evident inland from the towns. It appears that two specialized and separate economic sectors were going on: the pot-making and agricultural practice. Therefore, people may have specialized in the making of vessels, reaching a high level of skill in mastering the wheel. Studies have attempted to define skill, and one of the definitions is that skill is the outcome of time spent in performing an activity. Moreover, contracts would have existed between those who produced olive oil, those who manufactured the vessels and those who exported produce to Rome. Good, solid batches of amphorae had to be purchased by third parties, and to be filled with olive oil.

In Tripolitania, by contrast, settlement studies show that sites were equipped with oil olive processing facilities and pottery kilns, highlighting the rural and self-sufficient nature of production. All production, from olive oil, to amphora manufacturing, and bottling took place on site. It is very possible that people who harvested the olives, a seasonal job, could have made their own vessels. In this case, manufacturing error such as air pockets noticed on the vessels, did not matter, because there was no necessity to buy containers from a third party.

You might want to look back at the following sections of the Archaeology of Portus course:

• The links to other ports (Portus-1), (Portus-2), (Portus-3)
• The value of ceramics (Portus-1), (Portus-2), (Portus-3)
• Find of the Week – amphora sherds from Leptis Magna (Portus-1), (Portus-2), (Portus-3)
• Scientific Finds Analyses (Portus-1), (Portus-2), (Portus-3)
• Find of the week – fineware (Portus-1), (Portus-2), (Portus-3)

Reference cited in the text:

Budden, S. (2007) Renewal and Reinvention: the role of learning strategies in the Early to Late Middle Bronze Age of the Carpathian  Basin. Unpublished PhD thesis. University of Southampton.

More information is contained in Appendix 1: Technology as a Social Tool’ with relevant bibliography on technology and society, in my e-thesis:

(2012) African amphorae from Portus. University of Southampton, School of Humanities, Doctoral Thesis, 864pp.

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I provided a link to my PhD thesis early on in the course in Week One on the Find of the Week – amphora sherds from Leptis Magna step. In addition to this step I thought you might be interested to follow through from other steps to my thesis and vice versa. The “direct links” *should* take you to specific pages in the thesis, but the behaviour varies according to your device and setup. You can access the whole thesis in any case from the reference below.

I would welcome your comments on the FL platform or via this blog post.

(2012) African amphorae from Portus. University of Southampton, School of Humanities, Doctoral Thesis, 864pp.

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Ceramics are a very important type of archaeological evidence at sites, with the potential to inform us about chronology and society. They come up at various points in the Archaeology of Portus course and this blog posts provides some extra information based on my research. If you want to check back (or forward!) to relevant pieces of the course I would start with the following:

• The value of ceramics (week one)
• Find of the Week – amphora sherds from Leptis Magna (week one)
• Specialisms in studying the past (week two)
• Find of the week – fineware (week five)

One of the main applications of typological studies (study of a vessel’s shape) is to provide a chronological framework for excavated archaeological contexts upon which to base our understanding and interpretation of past activities taking place at an archaeological site. Study of the fabrics, that is the fired clay with its geological inclusions, allows us to provenance the ceramic materials. Typology, fabric, and petrological analysis represent standard methodologies for the study of ceramics, allowing us to make sense of a large amount of material found on archaeological sites.

The first step in any ceramic analysis is typological classification, including study of vessel shape and its morphological characteristics. This involves for example categorizing sherds from the site based upon similarities in their profile or shape, and comparing these with existing typologies from previous studies. This allows us to identify different types of vessel.

The second step in ceramic analysis is to look at the fabrics, based on the clay and inclusions used in making the pottery. A ceramic fabric consists of the fired clay matrix and its mineral or organic inclusions. These may occur naturally, or may be intentionally added to the clay by the potters. Fabric analysis, or fabric characterization, takes into account a number of variables, such as the colour, the degree of coarseness, the type of the main inclusions occurring in the fabric, and their frequency and distribution. This is generally carried out with a lens or a binocular microscope. The main application of fabric analysis is to provenance the archaeological ceramics, allowing us to delineate areas of exploitation or workshops of production, and to distinguish between local and imported pottery at an archaeological site.

A further stage in fabric analysis is that of petrological analysis. Petrology is the study of a cross-section of a ceramic sherd under a petrological microscope. By using a petrological microscope it is possible to identify geological inclusions according to their optical properties, and rock fragments where present, which may be distinctive of geological areas. This work requires the grinding down of a ceramic sherd to obtain a completely flat ceramic layer of ideally 0.03mm thickness, which is then fixed to a glass slide.

But what are Roman amphorae, and what can this type of vessel tell us? Roman amphorae are large to very large-sized vessels used for moving agricultural foodstuffs from one province to another. They carried mainly olive oil, wine, different kinds of fish products (salsamenta), and dried fruit. Amphorae are therefore very important evidence for studying the vital link between production and consumption in antiquity, and topics related to the Roman economy.

My study at Portus focused on North African amphorae, and in particular on those manufactured in Africa Proconsularis, which fall within modern Tunisia and western Libya. North African amphorae form the bulk of all ceramic materials at Portus, emphasizing the role of this province in supplying its ceramic and agricultural products to Rome. From the end of the 2nd century AD and in the 3rd century AD, a large amount of amphorae, carrying olive oil, reached Portus from central Tunisia and above all from Tripolitania (modern Libya).

One of the main aims of the research was to tie the amphora vessels down to their workshops and areas of production with the aim of providing a more defined view of the links between the North African suppliers and Portus. Based on an understanding of the principals of typology, fabrics and petrology, and on previous academic work within this field of research, the study identified a number of important workshops that worked in commercial partnership with Portus in the late 2nd and 3rd centuries AD, such as Sullecthum (central Tunisia), Leptis Magna and Tripoli and their rural hinterlands, and in the 4th and 5th centuries AD, such as Nabeul (northern Tunisia).

Focusing in particular on Sullecthum, a coastal port-town in central Tunisia, the pottery workshops manufactured most of the Africana 1A amphorae excavated at Portus. Sullecthum fabric is a very distinctive one. It is usually fired to produce two colours; red and greyish, while it contains numerous small white specks of limestone (Fig. 1 above).

A cross section of the sherd analyzed under the petrological microscope shows that this fabric is essentially a limestone-quartz fabric (limestone are the rounded and brownish inclusions, the quartz are white and rounded). It may contain small grains of pyroxenes, or volcanic minerals (these latter are very colorful under the petrological microscope, under crossed polars) (Fig. 2).

The Africana 1A carried olive oil, underlining the importance of this type of economy, based on olive trees growing in central Tunisia, as well as the commercial export activity to Portus.

Sullecthum fabric occurs also on the Africana 2A and on the Keay 25.1, although in a smaller amount (the full profile of the aforementioned vessels can be accessed on the AHRC Southampton amphora website: http://archaeologydataservice.ac.uk/archives/view/amphora_ahrb_2005/cat_amph.cfm). According to the current amphora literature, the Africana 2A traded fish sauce. This emphasizes the importance of a fish-based economy at the site, where fish-processing tanks have been excavated. Such produce from Sullecthum seems therefore to have been complementary to that of olive oil. The Keay 25.1 amphora is a later vessel, dating to the 4th century AD, and it is associated with wine, although other produce could be carried in this vessel.

The importance of Sullecthum to Ostia-Portus, and to Rome, is visible in comparative material from different types of archaeological evidence. At the Merchant Square in Ostia, the trading guild of Sullecthum is represented in the mosaics as one of Rome’s commercial partners (Fig. 3). A certain P. Caesellinus Felix, a citizen from Sullecthum, (from the latin civis Sullecthinus), was buried at Ostia, as recorded by a funerary inscription. He may have been involved in the trading activities taking place between Sullecthum and Portus as testified by the amphorae.

Bibliography

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Bonifay, M. (2004) Etudes sur la céramique romaine tardive d’Afrique (Oxford).

Bonifay, M., Capelli, C., Drine, A., Ghalia T. (2010) Les productions d’amphores romaines sur le littoral Tunisien. Archéologie et archéométrie. Rei Cretariae Romanae Fautorum Acta, 41, pp.319-327.

Capelli, C., Ben Lazreg, N., Bonifay, M. (2006) Nuove prospettive nelle ricerche archeometriche sulle ceramiche nordafricane: l’esempio dell’atelier di Sullecthum-Salakta (Tunisia centrale), in Cucuzza, N. and Medri, M. (eds) Archeologie: Studi in onore di Tiziano Mannoni (Bari), pp.291-294.

Keay, S. (1984) Late Roman Amphorae in the Western Mediterranean. A Typology and Economic Study: the Catalan Evidence (Oxford).

Keay, S. (2010) Portus and the Alexandrian Grain Trade Revisited, Bollettino Di Archeologia On Line I 2010/ Volume Speciale B/ B7/ 3. www.archeologia.beniculturali.it/pages/pubblicazioni.html I (2010), pp. 11-22.

Keay, S. and Paroli, L. (2011) Portus and its Hinterland. Recent Archaeological Research (London).

Keay, S., Millett (M.) and Strutt, K. (2005) Portus: An Archaeological Survey of the Port of Imperial Rome (London, 2005).

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Panella, C. (1973) Anfore. In A. Carandini and C. Panella (eds) Ostia III (Roma), pp. 463-633.

Peacock, D. P. S. (1977) Roman Amphorae: Typology, Fabric and Origins’, in D. P. S. Peacock (ed) Methods classiques et methods formelles dan l’etude des amphores, pp. 261-73.

Peacock, D. P.S (1984) Petrology and Origins. In M. Fulford and Peacock, D. P.S (eds) Excavations at Carthage: The British Mission I.2, The Avenue du Président Habib Bourguiba, Salambo: The Pottery and other Ceramic Objects from the site (Sheffield), pp. 6-28.

PCRG (1997) – Prehistoric Ceramic Research Group. The Study of Later Pre-historic Pottery. General Policies and Guidelines for Analysis and Publication. Occasional Papaers Nos 1 and 2.

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