Natron glass production and supply in the late antique and early medieval Near East: The effect of the Byzantine-Islamic transition (original) (raw)

Natron glass production and supply in the late antique and early medieval Near East: the effect of the Byzantine-Islamic transition (Phelps, Freestone, Gorin-Rosen and Gratuze J Arch Sci 2016)

Palestine and Egypt supplied the Mediterranean and Europe with virtually all of its glass for most of the first millennium CE. While the Muslim conquest in the 7th century saw major political and economic adjustment, immediate changes to material culture appear to have been minimal. This paper examines the impact of the Byzantine-Islamic transition on the natron glass industry of Palestine from the 7th to 12th century. A series of 133 well-contextualised glass vessels from selected excavations in modern day Israel have been analysed for major, minor and trace elements using LA-ICP-MS. These glasses are assigned to previously established primary production groups, allowing the elucidation of the chronology of key changes in glass production in the region. Results indicate a relatively abrupt compositional change in the late 7th - early 8th centuries, covering the reforming reigns of al-Malik and al-Walid, which marks the end of “Byzantine” glass production and the establishment of the furnaces at Bet Eli'ezer. At about this time there was an influx of glass of an Egyptian composition. Production of Bet Eli'ezer type glass appears to have been limited to a short time span, less than 50 years, after which natron glass production in Palestine ceased. Plant ash glass is first encountered in the late 8th-early 9th century, probably as a result of reduced local natron glass production creating the conditions in which plant ash glass technology was adopted. Egypt continued to produce natron glass for up to a century after its demise in Palestine. It is reasoned that the change and then collapse in natron glass production in Palestine may well have been as a consequence of a reduction in the quantities of available natron. This affected Palestine first, and Egypt up to 100 years later, which suggests that the factors causing the reduction in natron supply originated at the source and were long term and gradual, not short term events.

Glassmaking using natron from el-Barnugi (Egypt); Pliny and the Roman glass industry

Pliny the Elder describes the discovery of a process for making natron glass, which was widely used for much of the first millennium BC and AD. His account of glassmaking with natron has since been corroborated by analyses of archaeological glass and the discovery of large-scale glass production sites where natron glass was made and then exported. Analyses of Egyptian natron have shown it to be a complex mixture of different sodium compounds, and previous experiments to make glass with Egyptian natron have been unsuccessful. Here, natron from el-Barnugi in the Egyptian Nile delta, a site which also probably supplied Roman glassmakers, is used to produce glass. The experiments show that highquality glass, free of unreacted batch or bubbles, could have been produced from natron in its unprocessed form in a single stage, that larger quantities of natron would be required than has previously been anticipated, that the presence of different sodium-containing compounds in the deposit aided melting, and that negligible waste is produced. The implications for the identification of glass production sites, for the organisation of trade and for the supply of natron within and outside Egypt are discussed in the light of Pliny's accounts.

Mineral natron, plant-ash and high-alumina byzantine glass bracelets: Possible byzantine primary glass production in Asia Minor

Journal of Archaeological Science: Reports, 2024

In order to elucidate the supply and consumption of glass during the 4th and 10th century A.D, fragments of 28 glass bracelets and amulets, excavated at Thessaloniki (Greece) and its region, were analyzed. The compositional pattern of Thessaloniki's glasses was based on an alkaline plant ash, as a flux, and quartz, as a silica source, and showed that these samples represent four different glass compositional groups and production technologies, with the exception of one glass group with high alumina level that had not been previously recognized in the glass making traditions in the Mediterranean area. The compositional analysis of raw chunk glass materials and of most glass artefacts showed that these bracelets and amulets have been made with various combinations/mixing of ash, distinct plant ash types and natron, quartz and sand, which reveals that they have been produced in workshops that had access to vitreous artefacts of different compositions-which have been produced using distinct types of fluxes and silica source-indicating that these glasses are the result of extensive glass recycling processes. Furthermore, the chemical compositions of Thessaloniki's bracelets are similar with the ones found in other Balkan coeval sites, with compositional patterns inbetween natron and plant ash ranges, but also in other Byzantine sites as Pergamon. This similarity in chemical analysis revealed that the same technological choices have been made to produce the bracelets, namely they have been produced in workshops that had access to vitreous artefacts of different compositions which had been produced using distinct types of fluxes and silica sources. The rest of glass artefacts, that are characterized by high alumina levels and are distinct from the other established groups of plant ash glass and mixed plant ash-natron glasses, had not been recognized in the typical glass-making traditions of the Mediterranean. This high alumina glass group suggests a regional Byzantine primary glass production center in Asia Minor.

Glass Production in the First Millennium CE: A Compositional Perspective

Künstlichen Stein zum durchsichtigen Massenprodukt / From artificial stone to translucent mass-product. Editors: Klimscha, F., Karlsen, H. J., Hansen, S., Renn, J.: Berlin Studies of the Ancient World 67, Edition TOPOI, 245-263, 2021

The author discusses long term-trends in glass production during the 1st millennium CE. The systematic application of scientific methods on archaeological finds demonstrates the complexity of glass production and the trade networks in glass products. Due to the limited availability of natron nearly all glass originated from Egypt and Syria-Palestine from where raw glass was distributed to secondary workshops across Eu-rope and the Near East. This mode of production remained mostly constant during Antiquity and the early Middle Ages but a long-term decline in the availability of natron led to the restructuring of production from the 9th century onwards. Der Autor bespricht Langzeittrends der Glasherstellung im 1. Jahrtausend n. Chr. Die systematische Anwendung naturwis-senschaftlicher Methoden auf archäologische Funde wird be-nutzt um die Komplexität der Produktionsketten und Han-delsnetzwerke von Glasobjekten aufzuzeigen. Wegen der be-schränkten Verfügbarkeit von Natron wird sämtliches Roh-glas aus Ägypten und der Levante in europäische Glasverar-beitungsplätze gebracht. Dieses Netzwerk bleibt während der Antike und dem Frühen Mittelalter konstant, wird aber seit dem 9. Jahrhundert strukturell anders ausgerichtet.

White as Salt, Precious as Gold. Natron beyond Glassmaking

Anadolu/Anatolia Suppl. Series I.4. Vasıf Şahoğlu, Müge Şevketoğlu, Yiğit H. Erbil (edd.), Connecting Cultures. Trade and Interconnections in the Ancient Near East from the Beginning until the End of the Roman Period, 2019

In the thirty-sixth book of his Naturalis Historia Pliny the Elder has the opportunity for an excursus on the accidental introduction of natron as a flux for glassmaking. Nevertheless, critical analysis of the text gives the occasion to disclose new perspectives on a still neglected topic in archaeological research. In this paper a preliminary attempt is made to investigate the ‘other side’ of natron deposits exploitation, independently and much earlier than its experimentation in glass workshops. Literary sources, inscribed documents and archaeological evidence, especially from Egypt and Greece, from the Early Classical to the Late Imperial period are discussed trying to investigate the almost invisible traces of both properly said natron and counterfeit soda from different areas of Eastern Mediterranean.