MINERALOGICAL INVESTIGATIONS OF MEDIEVAL BRICK SAMPLES FROM BÉKÉS COUNTY (SE HUNGARY)

Brick samples from nine archaeological sites representing seven contemporary medieval settlements in Békés County (SE Hungary) were analysed by quantitative X‐ray powder diffraction, optical microscopic, scanning electron microscopic and coupled thermal analytical – evolved gas analytical methods. The aims of this study were to give a mineralogical–petrographical characterization of the brick samples, to gain possible information on the raw clay and the admixed materials, and to determine the firing techniques applied in medieval southeastern Hungary. The mineralogical composition of the samples suggests that the locally extracted clay was mixed with fluvial sand and wheat (Triticum monococcum L.) chaff. The moulded bricks were fired in clamps. The different degrees of calcite consumption suggest that the firing temperature ranged from ～750°C to ～950°C. Moreover, the well‐developed reaction coronas on calcite grains indicate long firing times, lasting perhaps several days.     

THE DETERMINATION OF BRICK PROVENANCE AND TECHNOLOGY USING ANALYTICAL TECHNIQUES FROM THE PHYSICAL SCIENCES*†

This work applies established analytical techniques from the physical sciences to Irish brick, in order to gather evidence of ceramic technologies, provenance and sources of raw materials. Petrographic microscopy, X‐ray diffractometry and scanning electron microscopy with an energy‐dispersive X‐ray diffraction attachment were used to study the brick of Rathfarham Castle, Dublin, built c. 1618, where clay brick was introduced in 1771. Local clay was fired in the laboratory and analysed in a similar manner. The petrography of the pointing mortar was studied in order to gather evidence of ceramic provenance. This paper concludes that the brick was hand‐ moulded with a silica‐based, predominantly non‐calcareous clay of glacial origin, gathered locally, including fluxes and a high percentage of non‐plastic material. The mineralogy and petrography of the brick, together with the presence of pebbles and a coarse matrix, suggest that the raw clay was probably gathered from a glacial deposit. The presence of abundant pebbles and colour inhomogeneities suggests a lack of processing of the raw clay. The brick was probably fired in clamps at top firing temperatures ranging from 750°C to above 900°C. Transformation of limestone temper involving the breakdown of calcite and the generation of calcium silicates, and the new formation of plagioclase, high‐temperature quartz, hematite and spinel were revealed. The presence of spinel in ‘hot spots’ indicates that fuel was added to the raw clay in order to assist firing.     

SIENESE ‘ARCHAIC’ MAJOLICA: A TECHNOLOGICAL STUDY OF CERAMIC BODIES AND COATINGS*

The aim of the present study is to reconstruct the production technology of Sienese ‘archaic’ majolica in the early decades of the 14th century ad . The integration of archaeological data with archived data revealed the presence of numerous workshops, suggesting that the Sienese tradition of majolica production was well developed up until the end of the 16th century. Sixty‐seven uncoated and coated waste products were analysed. The ceramic bodies were examined by OM, XRDp, SEM–EDS, XRF, ICP–OES, ICP–MS and INAA. The coatings (enamels and glazes) were analysed by SEM–EDS and Raman microspectroscopy. The results showed that ceramics were rejected due to poor control of the firing temperature (technological wastes), faulty production technology (wastes of uncertain classification) and accidents (post‐firing wastes). Finally, the analyses revealed extreme homogeneity of the ceramic bodies, indicating the continued use of the same raw material over the whole period studied.     

THE PROVENANCE AND PRODUCTION TECHNOLOGY OF BRONZE AGE AND IRON AGE POTTERY FROM TELL MISHRIFEH/QATNA (SYRIA)*

This work deals with the archaeometric study of the Bronze Age and Iron Age pottery from Tell Mishrifeh/Qatna (central‐western Syria), where the complete cycle of ceramic production is well documented. Petrographic, chemical and diffractometric analyses were carried out on both potsherds and a clayey material found in a separation basin within the area of the workshops. Petrographic groups were defined and maximum firing temperatures and redox firing conditions were estimated, providing constraints on identifying the production technology and its evolution with time. The studied potsherds turned out to be locally produced, with only a few cases of possible similarities with those described for other localities along the Orontes Valley, and in a couple of cases with evidence of pottery exchange.     

Inheritance relationship between Zhanggongxiang kiln celadon and Ru Guan celadon: Comments on the rationality of Raman Ip value evaluating firing temperature

The development of Chinese ceramics culminated during the Song dynasty. At this time, exquisite celadon works emerged, such as Ru Guan celadon and Southern Song dynasty official kiln celadon, which exhibited the glory of their era. Since the excavation of Zhanggongxiang kiln celadon in Ruzhou city, Henan province, China, it has been attracting widespread scholarly attention at home and abroad. Most scholars have suggested that Zhanggongxiang is the official kiln of the Northern Song dynasty. In this paper, taking the celadon unearthed from the Zhanggongxiang kiln as a sample, the combination of laser Raman spectrum and thermal expansion methods is used to study the inheritance relationship between Zhanggongxiang celadon and Ru Guan celadon in the firing process. Meanwhile, the rationality of using Raman I_p value to evaluate the firing temperature of ceramics is reviewed. The main conclusions are as follows. First, the firing temperature of Zhanggongxiang celadon with various glaze colours is quite different, whereas the firing temperature of the same glaze colour is similar, thereby inheriting the firing technology of Ru Guan porcelain. Second, the I_p value of glaze cannot evaluate the firing temperature of porcelain with similar firing temperature. The I_p value corresponds to a range, within which it does not fully conform to the rule that the larger the I_p value, the higher the firing temperature. The I_p value is also associated with the formulation in addition to firing temperature. It is applicable to evaluating porcelains with a similar formulation but a large temperature difference.     

A SCIENTIFIC INVESTIGATION ON THE PROVENANCE AND TECHNOLOGY OF A BLACK‐FIGURE AMPHORA ATTRIBUTED TO THE PRIAM GROUP*

The restoration of a Greek black‐figure amphora provided an opportunity to study the provenance and production technology of the vase. The composition of the ceramic body, determined by inductively coupled plasma optical emission spectroscopy (ICP–OES), matches that of Attic products. Investigation by X‐ray diffraction and reflectance spectroscopy suggests a maximum firing temperature around 900°C and a body re‐oxidation temperature around 800°C, respectively. The morphology and composition of black, red and dark red surface areas were studied by scanning electron microscopy and X‐ray energy‐dispersive analysis; the black areas show the features of a typical well‐vitrified black gloss, while the red areas were most probably obtained by simple burnishing of the body; the dark red additions, on the other hand, are the likely result of a partial re‐oxidation of a clay–ochre mixture.     

NETWORKS OF IRON: THE ROLE OF BLACKSMITHING IN MEDIEVAL COPENHAGEN

The information which can be extracted from studying craft and production in past societies is by no means limited to technology and exchange. Analysing the chaîne opératoire of iron production in medieval society provides a new perspective and knowledge of its role for urban development. Seen as a complex network of economic, social and material relations, craft and production are embedded in society and have the power to influence it. This article presents and discusses the remains of blacksmithing found at the site of Rådhuspladsen ('City Hall Square') in Copenhagen. The analysis focuses on the scale, types and organisation of the ironworking, as well as identifying the people who may have been involved, including their social and geographical networks. This study aims to better understand the role of iron production for the development of medieval Copenhagen and in general, its role in medieval Danish towns.     

METHODOLOGICAL DEVELOPMENTS IN THE LUMINESCENCE DATING OF BRICK FROM ENGLISH LATE‐MEDIEVAL AND POST‐MEDIEVAL BUILDINGS*

Fired clay brick samples, obtained from a group of seven high‐status late‐medieval and post‐medieval buildings in England ranging in age from c. ad 1390 to 1740, were dated by the luminescence method using an optically stimulated luminescence (OSL) technique. The results obtained indicate that, when applied to quartz extracted from brick, the technique is capable of producing dates that are in consistently good agreement with independent dating evidence for the buildings. For six samples taken from a group of four dating ‘control’ buildings the mean difference between the central values of luminescence and assigned ages was 5 ± 10 years (SD, n = 6). The methodology used is appropriate for application to other standing buildings in other temporal and geographic regions, and may be used with confidence where conventional dating methods are less certain. The study also examines the luminescence characteristics of quartz and the characteristics of the lithogenic radionuclides in brick samples and identifies various aspects related to the assessment of experimental uncertainty in testing the reliability of the method.     

Technology Transfer at the Periphery of the Mycenaean World: The Cases of Mycenaean Pottery Found in Central Macedonia (Greece) and the Plain of Sybaris (Italy)*

The study of technology transfer in pottery production to the periphery of the Mycenaean world has been addressed by considering two different areas, southern Italy and central Macedonia. Technological features such as ceramic paste, decoration and firing have been determined for different ceramic groups established according to provenance criteria. The studies of technology and provenance have been performed following an archaeometric approach, using neutron activation analysis, petrographic analysis, X‐ray diffraction and scanning electron microscopy. The results have revealed the existence of two different models. On the one hand, southern Italy seems to exhibit a more organized pottery production, which follows a Mycenaean‐like technology, while in central Macedonia production is probably more varied, being based in part on the technology of the local tradition.     

Archaeometric study of medieval pottery excavated at Stari (Old) Ras,Serbia

A combined study of a series of polychromatic and monochromatic glazed medieval pottery shards excavated from the archaeological area of Stari (Old) Ras in southern Serbia, including petrographic and chemical analysis, powder X-ray diffraction (PXRD) and Fourier transform infrared (FTIR) spectroscopy, allowed us to clearly distinguish between two groups of ceramics. Ras pottery, made of fine-grained well-cleaned clay and characterised by a rich mineral assemblage, was produced by firing in a temperature range between 800 and 900 °C. Reljina Gradina ceramics were produced at similar temperatures from materials which, with regard to mineralogical and chemical composition, show clear similarity with local clay, suggesting that these samples are of local origin and production. This work is the first systematic archaeometric study of medieval pottery excavated on the territory of Serbia.     

Glassmaking in Bagot’s Park,Staffordshire, in the 16th Century

Abstract

Out of 15 glass-making sites found in Bagot’s Park during land reclamation, one, Site 4, was left for examination. Two furnaces were excavated; the larger was for the melting of glass in six crucibles, and was typical of late medieval English practice, being built of brick and stone with a clay dome; it was the first to be excavated with clear evidence of an all-over timber and tile roof. The second, built partly of brick, was for annealing. The main product was Crown window glass; the amount of Broad glass and vessel found was insufficient to say with certainty that they were made on the site.

Archaeological evidence supported by documentary references suggested that the site was in use in the early 16th century, well before the agreement of 1585 between the Bagots and the Lorrainer Henzey family. Such evidence of glass production in this period suggests that the weakness of the English glass industry before 1567 may have been exaggerated.     

Recent Archæological Researches in Rome

Luminescence dating has been applied to ceramic bricks sampled from a selection of English medieval ecclesiastical and secular buildings in Essex, Kent and Lincolnshire, ranging in age from the fourth to the late sixteenth centuries. The results obtained for the Anglo-Saxon churches, which included Brixworth, confirmed the reuse of Roman brick in all cases. The dates for the earliest medieval brick type indicate that brick making was reintroduced during the eleventh century, a century earlier than previously accepted, and dates for bricks from the same secular Tudor building indicate that the practice of recycling of building materials during the late medieval period was also applied to brick.     

How the Romans got themselves into hot water: temperatures and fuel types used in firing a hypocaust

Abstract

The remains of hypocausts are noted as being widespread throughout the Roman Empire but, whereas the structure of hypocaust systems has been widely documented, primary knowledge of operating temperatures is limited. The petrographic technique of reflectance microscopy is used here to quantify cell wall reflectance values for charcoals from the hypocaust furnace of a bath suite forming part of small Romano-British villa complex at Groundwell Ridge near Swindon (Wiltshire, UK). The technique utilises material of archaeological origin to infer operating temperatures of the hypocaust furnace using established calibrations. The charcoals recovered from the furnace were identified as being predominantly Quercus (Oak) with some Populus/Salix (poplar/willow). Mean random reflectance of the samples indicated furnace-operating temperatures of 330–410°C. These temperatures fall below that of charcoal fuel production and hence suggest that it was wood that was used to fuel the hypocaust at Groundwell Ridge and not charcoal. Knowledge of the operating temperature of the furnace is a starting point in further calculations to understand, using primary evidence, the operating temperatures throughout the hypocaust system.     

The Mineralogical Characteristics of the Lamboglia 2 Roman‐Age Amphorae from the Central Adriatic (Croatia)*

The mineralogical characteristics of four Lamboglia 2 Roman‐age amphorae excavated from ancient underwater shipwreck localities in the central Adriatic were investigated. X‐ray diffraction and optical microscopy analyses showed that the amphorae have similar primary mineral compositions, mainly consisting of quartz, plagioclase, potassium feldspar, diopside, illite and calcite, most probably originating from clayey Eocene flysch deposits used as raw materials in manufacture. The difference in mineral composition between these samples is recognized from the presence or absence of melilite, high‐magnesium calcite, aragonite, gypsum and analcime. It was shown that melilite is a secondary mineral formed during the firing process, while the others, which build up through incrustation of marine benthonic communities on the amphora walls and fill the cracks in the amphora bodies, were formed by crystallization in seawater. The firing of the original pieces of amphorae showed that melilite could be formed at temperatures higher than 800°C, most probably through interaction between calcite and silicate minerals present in the raw materials. The presence of melilite, and the absence of illite and calcite, were used to estimate the firing temperature of the amphorae during their production.     

ROMAN GLASS‐MAKING AT COPPERGATE,YORK? ANALYTICAL EVIDENCE FOR THE NATURE OF PRODUCTION*

Ceramic vessels and associated vitreous debris, excavated at Coppergate, York, UK, have been interpreted as the remains of Roman glass‐making from the raw materials. This paper reports the results of analysis of this assemblage by XRF, ICPS, XRD, SEM– EDAX and thin‐section petrography. These findings suggest that some ceramic vessels, used as crucibles, have been subjected to temperatures up to 1200°C, well above the firing temperatures of the local domestic assemblage from which they were selected. Analysis of quartz‐rich debris, intimately mixed with glass in some samples and in others interleaved with glassy phases, indicates partially reacted glass‐making raw materials, with α‐quartz, tridymite and cristoballite phases represented. This could represent evidence either of a failed attempt to frit the raw materials, or a batch that had not fully fused. Variability in the composition of glass at the site is viewed in the light of glass‐making technology, and possible interpretations concerning this episode are discussed in the light of the archaeological evidence.     

LEAD GLAZES IN ANTIQUITY—METHODS OF PRODUCTION AND REASONS FOR USE*

Transparent high lead and tin-opacified lead-alkali glazes have been extensively used throughout Europe and the Near East from their first appearance in the Roman era and the tenth- to eleventh-century Islamic world, respectively, up until the present day. Using, to a large extent, information which is widely scattered through a diverse range of literature, the methods employed in the production of these two glaze types are first outlined and their merits are then compared with those of alkali glazes in terms of ease of preparation of the glaze mixture, ease of application of the glaze, ease of firing, cost of production, glaze-body fit and visual appearance. The principal advantages of transparent high lead glazes as compared to alkali glazes are shown to be ease of preparation and application of the glaze suspension, low susceptibility to glaze ‘crazing’ and ‘crawling’ and high, optical brilliance. Factors that influence the choice of tin-opacified lead-alkali glazes include ease of production of tin oxide by melting tin and lead metals together; a reduced risk of reduction of lead oxide to lead metal and consequent blackening of the glaze; and, again, low susceptibility to ‘crazing’ and ‘crawling’. Limits of current knowledge regarding these two glaze types and requirements for future research are outlined.     

INCISED SLIPWARE PRODUCTION AT CASTELFIORENTINO (FLORENCE): THE ‘VIA BERTINI’ SITE (15TH–17TH CENTURIES)*

This study deals with the physical–chemical and mineralogical–petrographic investigations (OM, SEM–EDS, EPMA, ICP, XRpD, Mössbauer and IR) conducted on first‐ and second‐firing wasters belonging to two types of incised slipware (sgraffito), manufactured at Castelfiorentino between the late 15th and the early 17th centuries. Raw materials, colouring agents and firing products were analysed in order to establish the production technology of the ceramic coatings, by means of detailed microtextural and chemical investigations. The pottery underwent two firing processes: the firing of the white slip‐coated ceramic body and a further firing after application of the glaze. The homogeneity of the raw materials, white slip and glaze is remarkable, and demonstrates the use of well‐established recipes with a constant supply of raw materials from the same places. Highly efficient kiln management during both firings is revealed by body–glaze interface reactions.     

Charcoal analysis of industrial fuelwood from medieval and early modern iron-working sites in Bilsdale and Rievaulx,North Yorkshire,UK: evidence for species selection and woodland management

Abstract

This paper presents the results of species diversity and dendrological analyses of archaeological charcoal excavated from medieval and early modern iron production sites in Bilsdale, and at Rievaulx in the neighbouring valley of Ryedale, North Yorkshire, UK. Standard methods of quantification are used to assess species diversity, sampling sufficiency and taxa presence. The assessment of dendrological features provides additional evidence for growth trends and cutting cycles analogous with cyclical woodland management, as well as environmental and growing conditions. Analysis of archaeological charcoal from four medieval bloomery furnace sites in Bilsdale, and from the site of the hammersmithy and blast furnace at the early modern iron works at Rievaulx, provide comparable data-sets which indicate a change in cutting practise and dominant species selection for industrial fuelwood occurred between the 12th- and mid-16th centuries AD. Results show that dominant species presence changed from an admixture of predominantly birch (Betula sp.) and hazel (Corylus avellana) sourced from small calibre branchwood and stemwood used in the medieval bloomery furnaces, to a dominant oak (Quercus sp.) presence from standard sources used at the Rievaulx iron works by the mid-16th century. Whilst it is uncertain whether this change in dominant species composition and the source of industrial fuelwood is related to changes in local availability, or the result of the technological transition to blast furnace processing which occurred at this time, estate records reveal a woodland management campaign was instigated to supply and maintain fuelwood supplies to the iron works at Rievaulx which coincides with the introduction of Tudor arboricultural legislation in the 1540s.     

ROMAN AND MEDIEVAL GLASS FROM THE ITALIAN AREA: BULK CHARACTERIZATION AND RELATIONSHIPS WITH PRODUCTION TECHNOLOGIES*

Compositional investigations were performed on 81 Roman and medieval glass fragments (first to 14th centuries ad ) from four Italian archaeological sites. The samples were soda–lime–silica in composition, with natron as flux for the Roman and early medieval glass samples, and with plant ash as flux for the late medieval ones. The varying colours are due to the differing FeO, Fe ₂ O ₃ , MnO and Sb ₂ O ₃ contents. Hierarchical cluster analysis identified six compositional groups related to age, which were compared with those found in the literature. In this way, technological continuity from the Roman to the early medieval period and the appearance of plant ash technology in the ninth century, 200 years in advance of the period previously believed, are demonstrated.     

MICROSCOPIC IDENTIFICATION AND SOURCING OF ANCIENT EGYPTIAN PLANT FIBRES USING LONGITUDINAL THIN SECTIONING*

Plant fibres and the artefacts constructed from them often remain overlooked in the archaeological record because of their poor survival and the problems related to the precise identification of the species to which the fibres belong. The goal of this study was to design a simple and accurate method of identifying archaeological plant fibre sources. Twenty‐two fibre samples from two sets of ancient Egyptian botanical artefacts were examined under both a stereomicroscope and a compound microscope, and compared to a large reference collection and to previously published research. By examining longitudinal thin sections of the ancient plant specimens, we identified plant fibres from the following species: Hyphaene thebeica, Cyperus papyrus, Desmostachya bipinnata, Imperata cylindrica, Phragmites australis and Linum usitatissimum. Our identification of these plant fibres reveals essential information about the materials used for producing ropes, baskets, sandals, mats and fabric. The results of this study demonstrate the value of longitudinal thin sectioning and light microscopy as a major means of identifying the source material of botanical artefacts, and advance our knowledge of ancient Egyptian plant exploitation as well as the associated technologies involved in constructing these types of artefacts.