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XII/2/2021
INTERDISCIPLINARIA ARCHAEOLOGICA
NATURAL SCIENCES IN ARCHAEOLOGY
homepage: http://www.iansa.eu
The Use of the Wheel in the Production of Pithoi: Preliminary Results and
Lessons Learnt from Experimental Sessions
Francesca Porta
1*
1
UCLouvain, INCAL/CEMA/AEGIS Research Group Department, Place Blaise Pascal 1, 1348, Louvain-la-Neuve, Belgium
1. Introduction
Pithoi, 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
pitharakia
in 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.com
ARTICLE INFO
Article history:
Received: 1
st
February 2021
Accepted: 14
th
August 2021
DOI: http://dx.doi.org/10.24916/iansa.2021.2.4
Key words:
Pithoi
Experimental Archaeology
Wheel-coiling
Slab-building
Bronze Age
ABSTRACT
Large earthenware storage vessels, known as
pithoi, 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.
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author (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-ray
images 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-ray
s. Although
X-ray
s 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-ray
images of
experimental items.
2. Material and Methods
The methodology applied in this study consists of
a combination of experimental archaeology, macroscopic
inspection and
X-ray
analysis 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-ray
ed at the Radiology
Department at the Trebisacce Hospital, Calabria, Italy, by
F. Odoguardi using a Carestream CR 975
X-ray
machine.
By
X-ray
ing 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-ray
markers, 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-ray
images, 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-ray
image 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 Italy
In 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, pithoi
became 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
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use 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 Experiments
The 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-ray
s. 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-ray
traces. 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) – FBA
The 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