image/svg+xml155XII/2/2021INTERDISCIPLINARIA ARCHAEOLOGICANATURAL SCIENCES IN ARCHAEOLOGYhomepage: http://www.iansa.euThe Use of the Wheel in the Production of Pithoi: Preliminary Results and Lessons Learnt from Experimental SessionsFrancesca Porta1*1UCLouvain, INCAL/CEMA/AEGIS Research Group Department, Place Blaise Pascal 1, 1348, Louvain-la-Neuve, Belgium1. IntroductionPithoi, large earthenware storage vessels, were widespread in the Mediterranean area, both in domestic and non-domestic contexts, such as palaces and temples, throughout the Bronze Age (Bevan, 2014; Cyprus: Pilides, 2000; Shuster Keswani, 2009; Crete: Christakis, 2005; Privitera, 2010; Northern Greece: Margomenou and Roumpou, 2011; Anatolia: Kibaroğlu and Thumm-Doğrayan, 2013; Southern Italy and Sicily: Guglielmino, 1999; Schiappelli, 2003; 2015; and Veca, 2015). The importance of pithoi and pitharakiain the Mediterranean is further attested to by their continued production until more recent times, as verifed through ethnographic research (Hampe and Winter, 1962; Voyatzoglou, 1974; Blitzer, 1990; Giannopoulou and Demesticha, 2008; Giannopoulou, 2010).Due to their demanding manufacturing process, pithoi are considered a form of specialised pottery production (Levi, 1999; Giannopoulou, 2010, pp.55–77), and studies on their production technology potentially allow scholars to gather information about productive systems, craft skills, diferent levels of specialisation (Shuster Keswani, 2009), and on the organisation of economic systems (Christakis, 2008; Manzanilla and Rothman, 2016). However, technological studies, especially regarding the identifcation of forming methods, stand out due to their relative rarity (Levi, 1999; Preston Day et. al., 2016;Vankilde, 2016; Keswani, 2017).This paper presents the initial results from two diferent experimental sessions dedicated to the investigation of the use of the wheel to produce large clay containers. In the case of pithoi, the wheel could only be linked to wheel-fashioning methods (Roux, 2019, pp.84–92; Jefra, 2011; Roux and Courty, 1998), as the production of such large-sized vessels by way of wheel throwing is considered impossible.Independent of the specifc techniques utilised, wheel-made vessels present macro traces such as horizontal and parallel rilling striations and grooves on their surfaces. However, as already stated, surface features may be polysemic as they can be the result of diferent formation processes (Courty and Roux, 1995, p.18). Thus, it is necessary to explore the relationship between formation techniques/methods and macro traces on vessels made by way of experiment.The experiments presented here were part of a broader study of pithoi-manufacturing technology carried out by the Volume XII ● Issue 2/2021 ● Pages 155–171*Corresponding author. E-mail: f.porta87@gmail.comARTICLE INFOArticle history:Received: 1stFebruary 2021Accepted: 14thAugust 2021DOI: words:PithoiExperimental ArchaeologyWheel-coilingSlab-buildingBronze AgeABSTRACTLarge earthenware storage vessels, known aspithoi, were very widespread in the Mediterranean Basin area, both in domestic and non-domestic contexts, throughout the entire Bronze Age. From a technological point of view, due to their large dimensions, the production of pithoi is very demanding and requires highly skilled and expert artisans. However, despite their large difusion and their prominent role in resource management, pithoi have received less attention in terms of research in comparison to other types of vessels; technological studies, in particular, stand out for their relative rarity. Indeed, experimental approaches are scant, thus preventing a comprehensive understanding of the manufacturing process of pithoi. This paper presents the preliminary results of two experimental sessions dedicated to the examination of the use of the wheel in the manufacture of these large clay containers. Experimental vessels have been analysed by way of the naked eye and through X-ray analysis.
image/svg+xmlIANSA 2021 ● XII/2 ● 155–171Francesca Porta: The Use of the Wheel in the Production of Pithoi: Preliminary Results and Lessons Learnt from Experimental Sessions156author (Porta, 2019) involving Late Bronze Age (hereafter LBA) pithoi found in Italy (Levi, 1999; Guglielmino, 1999; Schiappelli, 2003; 2015), Crete (Christakis, 2005), and Cyprus (Pilides, 2000; Shuster Keswani, 2009). Observation of the surfaces of the vessels combined with the analysis of their X-rayimages allowed one to hypothesise that some of these pithoi were made by way of the progressive stacking of clay elements (e.g.coils or slabs), with the use of the wheel (cf.Levi, 1999). The experiments were thus meant as a complementary tool to the research being carried out in order to test the suggested hypothesis (Ascher, 1961; Coles, 1979; Reynolds, 1999; Outram, 2008; O’Sullivan et. al., 2014; Jefra, 2015), and they were used to gather together a collection of examples of forming traces to be compared with those of the LBA pithoi. At present, experimental collections dedicated to the manufacture of pithoi and large vessels are missing. This biases the possibility to fully understand and interpret technological traces of ancient pithoi, since the formation of the traces and their fnal aspect can be completely diferent from the ones of smaller vessels.Experimental replicas were then analysed using macroscopic inspection and X-rays. Although X-rays and other microscopic analytical techniques (cf.Thér, 2016) are increasingly included in pottery technological studies, they are mainly used directly on archaeological samples and not tested against experimental (Berg, 2008) or ethnographic materials (Porta, 2019). This can lead to misconceptions when identifying traces, so rendering results incomplete and speculative (Livingstone Smith and Viseyrias, 2010). For this reason, a large amount of research has been dedicated to the study of X-rayimages of experimental items.2. Material and MethodsThe methodology applied in this study consists of a combination of experimental archaeology, macroscopic inspection and X-rayanalysis in order to address the identifcation and investigation of the pithoi-manufacturing process. The experimental framework was organised in two separate and diverse macro sessions, namely Experiments No. 1 and No. 2. All the experimental sessions were flmed and photographed, and all the parameters used (e.g.the amount of clay used, the manufacturing time and the turning speed of the wheel) were recorded. The experimental vessels produced were subsequently analysed by way of macroscopic inspection. Macro traces identifed on the external and internal surfaces and the cross-sections were classifed according to defnitions already established in previous academic research (Courty and Roux, 1995; Roux and Courty, 1998; Jefra, 2011; Choleva, 2012).Replicas of the sample in question were further analysed by way of X-ray. Materials were X-rayed at the Radiology Department at the Trebisacce Hospital, Calabria, Italy, by F. Odoguardi using a Carestream CR 975 X-raymachine.By X-raying the internal structure of the vessels, it was possible to observe the orientation of their inclusions and the orientation and shape of the voids imprinted by the primary forming methods. The ability to understand the internal structure of the vessels largely depends on the contrast between the clay matrix and the inclusions/voids within. The use of a very fne clay matrix, such as modern industrial clay, or an excessive quantity of temper can both obscure the manufacturing traces and preclude the identifcation of the manufacturing technique (Laneri, 2009, p.49; Berg, 2008, p.1186). For this reason, in Experiment No. 2, a specifc amount of temper and X-raymarkers, namely, manganese oxide (Desogus et. al., 1995), was added to the industrial clay to better identify technological traces. Moreover, in order to make the X-rayimages, usually in shades of grey, suitable for technical analysis, some modifcations of the contrast parameters were needed. Modifcations made the images clearer (white) or darker (black) in order to render the reading of the voids and inclusions easier; in the dark/black ones, porosities and cracks get very dark, while in the white ones, they get very clear. Internal traces visible in the X-rayimage were classifed according to the defnitions set out in Berg (2008; 2009 and 2011) and Livingstone Smith and Viseyrias (2010).2.1 Late Bronze Age Pithoi found in Southern ItalyIn the Italian archaeological chronology, the LBA corresponds to two diferent phases, specifcally the Recent Bronze Age (hereafter RBA, ca. 1325 to 1150 BC) and the Final Bronze Age (hereafter FBA, ca. 1150 to 990 BC) (Iacono et. al., 2021).The production of large pithoi using levigated clay started in Southern Italy during the RBA. It commenced after contact with the Aegean area, leading to the introduction of the wheel device for pottery production; unknown until that time. In general terms, a clear diference is visible between the RBA pithoi and those of the FBA (Levi, 1999; and Schiappelli, 2003; 2015) (Figure 1). The known RBA specimens were probably barrel-shaped with no complete specimens being noted thus far, and they were decorated with wide plain bands. Sometimes these bands bear incised/impressed patterns such as zig-zag or chevrons, as well as circles, criss-cross and herringbone. During the FBA, pithoibecame larger than in the previous phase, being ovoid-globular in shape with a wide mouth, though the mouth was limited in comparison to the maximum diameter of other vessels. Small vertical handles were placed directly on the rim. The decoration consisted of horizontal grooves or a band with two, three or four ribs. Other specimens present ropes with impressed decorations. In the same way as in the RBA, decorations were placed on the main conjunction or join points of the vessels in order to reinforce them.From a technological point of view, the presence of coils (or slabs) is clearly discernible in pithoi from cross-sections of fragments, as well as in wall thickenings in correspondence to the join point between two of them. Internal and external surfaces present fne- and medium-type rilling suggesting the
image/svg+xmlIANSA 2021 ● XII/2 ● 155–171Francesca Porta: The Use of the Wheel in the Production of Pithoi: Preliminary Results and Lessons Learnt from Experimental Sessions157use of the wheel in their production. As the RBA and FBA difer typologically, as the vessels were made diferently, RBA pithoi were probably made assembling large sections composed entirely of coils (Levi, 1999; Jones et. al., 2014; Schiappelli, 2015; Porta, 2019), conversely, as regards the FBA pithoi, each coil/slab was probably added to the previous one with the use of the wheel. The breakage mode refects these diferences in forming methods. In the RBA specimens, the main fractures run horizontally and are located in the join point between the sections where clay bands were usually positioned as reinforcements. By contrast, FBA pithoi breaks tend to be oblique or petal-shaped (for the defnition of petal-shaped, see Levi, 1999, p.175).2.2 The ExperimentsThe overall aim of the experiments was to create an experimental collection of vessels to correlate with the LBA pithoi found in Southern Italy, Crete and Cyprus. Experimental vessels were used to explore the possibility that the LBA pithoi were produced using the wheel and not just simply refned on it. This was done thanks to the investigation of the relationship between the forming techniques, macroscopic traces on the surfaces, and traces detected using X-rays. The two diferent experiments conducted responded to diferent necessities. Experiment No. 1 aimed to test the reasonableness of the hypothesis that during the FBA in Southern Italy, pithoi were made assembling large coils or slabs, each with the use of the wheel (Levi, 1999, p.203; Porta, 2019). In fact, Experiment No. 1 was based on the evidence of FBA pithoi unearthed in Broglio; the replica of Broglio pithos was realised with raw materials compatible with their ancient equivalent (Levi, 1999), and with the use of traditional tools and a non-motorised wheel type. In this sense, Experiment No. 1 could be classifed as an actualistic (Outram, 2008, p.2) or imitative experiment (Ascher, 1961; for a more general discussion, see Jefra, 2015).Experiment No. 2 responds to another requirement, being mainly used to verify the consistency of the wheel-coil methods noted in research studies with the production of large containers, and thus to produce the frst referenced collection of macro and X-raytraces. For this reason, Experiment No. 2 did not consider any clay recipes, and it was performed operating with an electric wheel. This allowed the comparison of experimental items to pithoi produced in diferent Mediterranean areas, for example, Southern Italy, Crete and Cyprus, (Porta, 2019), and the fostering of comparative studies between them. In this way, this second experiment should be viewed as a general framework and a stepping stone for further context-orientated experiments, that is, actualistic and/or imitative.2.2.1 Experiment No. 1 –. Replica of the Broglio di Trebisacce Pithos (BT) – FBAThe frst experiment, Experiment No 1, is part of a broader set of experiments carried out over the last few years at the Archaeological Park in Broglio di Trebisacce (Calabria, Italy) by a research team led by Alessandro Vanzetti (Sapienza University of Rome). Such experiments were realised in collaboration with G. Pulitani, a professional potter and craftsman. Jones et. al.(2014, pp.393–402) provides a detailed report and an extensive commentary about these experiments. A further experimental session was carried out in 2015. It was specifcally designed to address the reproduction of a FBA pithos based on the evidence recorded about the pithoi of Broglio di Trebisacce. The experimental pithos was produced using local clay extracted from the Trebisacce outcrops dating to the Pliocene Age; they were still exploited by local potters and brick manufacturers up