The ways in which glass was exchanged throughout ancient times is intimately related to its production and is a stepping stone to learning about the economies and interactions of ancient societies. Because of its nature it can be shaped into a variety of forms and as such is found in different archaeological contexts, such as window panes, jewellery, or tableware. This is important because it can inform on how different industries of sections of societies related to each other – both within a cultural region or with foreign societies.
Glass trade is mainly studied by compositional analysis of glass objects creating groups with specific chemical compositions that hopefully allow to differentiate between production centres (both geographically and chronologically). Complications arise from the fact that for long periods of time glass was made following very similar recipes and as such the major elements found do not vary significantly. It is made by a mixture of raw materials which means that different sources of each raw material even for the same production centre further complicate the situation. That it is a material that lends itself well to recycling can only add to this. However, as scientific techniques improve it is becoming increasingly possible to discern some compositional groups, together with other archaeological and textual evidence a picture of glass technology, industry and exchange is starting to emerge.
Glass beads are known from the 3rd millennium BC, but it is only in the late 2nd millennium that glass finds start occurring more frequently, primarily in Egypt and Mesopotamia. This is not to say that it was a widespread commodity; quite the contrary. It was a material for high-status objects with archaeological evidence for the Late Bronze Age (LBA) also showing an almost exclusive distribution of glass finds at palace complexes such as that found in the city of Amarna, Egypt. Texts listing offerings to Egyptian temples would start with gold and silver, followed by precious stones (lapis lazuli) and then bronze, copper and semiprecious stones, with glass mentioned together with the lapis lazuli. In this period it was rare and precious and its use largely restricted to the elite. [1]
Production of raw glass occurred at primary workshops, of which only three are known, all in Egypt: Amarna, Pi-Ramesses and Malkata. [2] At the first two sites cylindrical ceramic vessels with vitrified remains have been identified as glass crucibles, [3] [4] where the raw materials (quartz pebbles and plant ash) would be melted together with a colourant. The two sites seem to show a specialisation in colour, with blue glass, via the addition of cobalt, being produced at Amarna and red, through copper, at Pi-Ramesses. The resulting coloured glass would then be fashioned into objects at secondary workshops — far more common in the archaeological record. It seems certain that glass making was not exclusive to Egypt (in fact, scholarly opinion resides with the industry having originally been imported into the country) as there are Mesopotamian cuneiform texts which detail the recipes for the making of glass. Further supporting this hypothesis are the Amarna Letters, a contemporaneous diplomatic correspondence detailing the demand and gift giving from vassal princes in Syro-Palestine to the Egyptian king; in these the most requested item is glass.
The evidence then points to two regions that were making and exchanging glass. [5] It seems logical to believe that at an initial stage it was glass objects, as opposed to raw glass, that were exchanged. The major element composition of glass finds from Mesopotamia and Egypt is indistinguishable, with as much variation found within a specific assemblage as between different sites. This is indicative of the same recipe being used in both regions. As analytical techniques develop the presence of trace elements can be more accurately determined, and it has been found that glass is compositionally identical within each region, but it is possible to discriminate between them[ clarification needed ]. [6] This could allow us to uncover trade patterns; however, at present no Egyptian glass has been found in Mesopotamia, nor has any Mesopotamian glass been found in Egypt. [2]
Across the sea, Mycenaean glass beads were found to have been made with glass from both regions. The fact that the beads are stylistically Mycenaean would imply an import of raw glass. [2] Archaeological evidence for this trade comes from the Uluburun shipwreck, dated to the late 14th century BC. Part of its cargo consisted of the earliest known intact glass ingots: about 175 ingots of cylindrical shape, in blue shades from lavender to turquoise, as well as uncolored ones. [7] Some ingots chemically match the glass found in the Egyptian production sites; specifically, they match by shape the melting crucibles found at Amarna. [8]
It is not yet possible to discern if trade in glass was occurring directly between the glass producing regions and foreign consumers. It is possible that there were indirect routes via trading and seafaring partners along the Mediterranean coast. Trace element analysis of the Uluburun ingots might allow us to learn more. At this point we know glass was being consumed by the elites of Eastern Mediterranean and Western Asia; that it was produced in Egypt and Mesopotamia with workshops possibly specialising in colour and distributed locally, presumably through state control to state-sponsored artisans; and that it was exported further as raw glass ingots.
From Hellenistic times glass production sees considerable technological developments, culminating with the introduction of glass blowing in the 1st century BC. Glass objects could now be made in large scale production, faster and with less raw material, consequently becoming more common. From the early Roman times, to Byzantine and early Islamic periods the glass from Northern Europe to Eastern Mediterranean shows an incredible compositional homogeneity in its major elements. Unlike late bronze age glass, Roman glass was made from melting sand and natron – mineral soda – from the Wadi Natron in Egypt. [9] With one raw material being common to all glass, it should be possible to differentiate between glass made from different sands by analyzing compositional variations of the trace elements and certain isotope ratios. [10] These compositional analyses aimed to investigate two models for glass production: that glass was produced in large scale primary workshops along the Levantine coast [9] and Egypt, [11] mixing natron and sand from the mouth of the Belus river – as mentioned by Pliny – and then traded to local glass working workshops. If natron was traded and mixed with local sands following a strict recipe, it could result in the homogeneous composition.
Glass making furnaces have been uncovered in Israel at two sites – 17 at Bet Eli'ezer and 3 at Apollonia. [12] These are rectangular in shape measuring about 2m x 4m and matching the size of a glass slab found inside a cave at Bet She'arim. The resulting slabs would be broken up into chunks that were traded to glass workshops in the Middle East and across the Mediterranean, as evidenced by the contemporaneous shipwrecks carrying such glass chunks. [12]
The situation is not so simple; these workshops are dated from the 6th to the 11th century AD and while similar, the compositions do not exactly match those of the earlier Roman period. Pliny, writing in the 1st century AD, describes glass making in the Levantine coast but also in Italy, Spain and Gaul – however, any installations that could produce the large quantities of primary glass needed to supply the Roman industry have yet to be located. [13] These same authors report a difference in isotopic ratios for oxygen and strontium that differentiates between Middle Eastern and Roman glasses. Other authors have countered the idea of a unique centralized production, with primary production reported from Northern Europe [14] and inferred for Italy. [15] Evidence for large scale production has only come from the Eastern Mediterranean and from latter dates, and assumes a continuing glass making tradition. That there was a large scale and centralised production even this early is evidenced by the Ouest Embiez I shipwreck – 3rd century – carrying 8 tons of raw glass. [16] This does not exclude smaller scale local production reported elsewhere, however. The Julia Felix, also sunk during the 3rd century AD, was carrying as part of its cargo glass cullet, presumably for recycling. [17] Trace element analysis of colourless glass showed these were made using sands from different sources, giving some support to the de-centralised production hypothesis.
By the 9th century, the raw materials for glass shift again to quartz pebbles and plant ash, the 'forest glass' of medieval Europe. Natron was no longer in use, and the low lime composition of the Bet'eliezer glass could suggest declining access to the material from at least the 6th century onwards. [18] This could, in turn, suggest a shift from natron and raw glass trade toward tighter control over natron and increasing centralised production.
Glass shows up in Northern India at the end of the 2nd millennium BC, becoming more common throughout South East Asia during the following millennium. Glass beads in particular become extremely popular and, together with bangles, form the largest group of glass finds. From its Indian origins, glass beads spread as far as Africa and Japan, sailing with the monsoon winds, hence their being referred to as 'trade wind beads'. [19] The most common compositional type, representing 40% of the glass finds for the region, is known as mineral soda-alumina glass [20] and is found from the 4th century BC to the 16th century AD. As the name indicates, it is typically characterized by a high alumina content and was probably made by melting reh with local alumina rich sands. [21] Through LA-ICP-MS analysis, however, Carter found that Cambodia had a large amount of glass beads made of potash glass and predominantly high alumina soda glass. Potash glass is a glass that uses potash or K2O as a flux in order to decrease the melting point of the glass and is the most common type of glass found in SE Asia. [22]
Detailed compositional data recently summarised by (Lankton, & Dussubieux 2006) has uncovered several distinct and yet contemporaneous glass technologies across the Indian Ocean, but the geographical assignment is not completely clear. Two small groups show compositions matching those of natron-based Mediterranean glass and plant-ash Mesopotamian glass, demonstrating trade with these other regions. Trade in raw glass from Egypt to India was described in the 1st century texts of Periplus of the Erythraean. The presence of Mesopotamian glass increases with increased Sasanian control of the Indian Ocean from the 4th to 6th centuries. It is also possible that some glass was traded via the Silk Road.
The majority of glass beads found in Sub-Saharan Africa predating European contact are from Indian or Sri Lankan origin with a recent paper (Dussubieux et al. 2008) demonstrating contact between Kenyan sites and Chaul on the west coast of India from the 9th to 19th centuries. Previously analysed samples from the East coast of Africa and Madagascar could potentially fit this group, but further work is still needed. Whether Chaul was the single port for trade in glass beads or part of several competing ports on that coast is still unknown. Data from a site in South Africa, near the borders with Botswana and Zimbabwe, has tentatively assigned some beads to Islamic 8th century compositions. [23] This suggests that the old camel caravan routes that connected this region to Egypt and the Mediterranean were still in use even for glass at a site with easy access, via the Limpopo river, to the Indian Ocean trade and therefore to the West Indian glass that seems to be the most common. There is enough evidence that in ancient Sri Lanka, glass was manufactured in order for use in magnifying glasses or spectacles.
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: CS1 maint: multiple names: authors list (link)The Uluburun Shipwreck is a Late Bronze Age shipwreck dated to the late 14th century BC, discovered close to the east shore of Uluburun, Turkey, in the Mediterranean Sea. The shipwreck was discovered in the summer of 1982 by Mehmed Çakir, a local sponge diver from Yalıkavak, a village near Bodrum.
Egyptian blue, also known as calcium copper silicate (CaCuSi4O10 or CaOCuO(SiO2)4 (calcium copper tetrasilicate)) or cuprorivaite, is a pigment that was used in ancient Egypt for thousands of years. It is considered to be the first synthetic pigment. It was known to the Romans by the name caeruleum. After the Roman era, Egyptian blue fell from use and, thereafter, the manner of its creation was forgotten. In modern times, scientists have been able to analyze its chemistry and reconstruct how to make it.
Egyptian faience is a sintered-quartz ceramic material from Ancient Egypt. The sintering process "covered [the material] with a true vitreous coating" as the quartz underwent vitrification, creating a bright lustre of various colours "usually in a transparent blue or green isotropic glass". Its name in the Ancient Egyptian language was tjehenet, and modern archeological terms for it include sintered quartz, glazed frit, and glazed composition. Tjehenet is distinct from the crystalline pigment Egyptian blue, for which it has sometimes incorrectly been used as a synonym.
A frit is a ceramic composition that has been fused, quenched, and granulated. Frits form an important part of the batches used in compounding enamels and ceramic glazes; the purpose of this pre-fusion is to render any soluble and/or toxic components insoluble by causing them to combine with silica and other added oxides. However, not all glass that is fused and quenched in water is frit, as this method of cooling down very hot glass is also widely used in glass manufacture.
Anglo-Saxon glass has been found across England during archaeological excavations of both settlement and cemetery sites. Glass in the Anglo-Saxon period was used in the manufacture of a range of objects including vessels, beads, windows and was even used in jewellery. In the 5th century AD with the Roman departure from Britain, there were also considerable changes in the usage of glass. Excavation of Romano-British sites have revealed plentiful amounts of glass but, in contrast, the amount recovered from 5th century and later Anglo-Saxon sites is minuscule.
Roman glass objects have been recovered across the Roman Empire in domestic, industrial and funerary contexts. Glass was used primarily for the production of vessels, although mosaic tiles and window glass were also produced. Roman glass production developed from Hellenistic technical traditions, initially concentrating on the production of intensely coloured cast glass vessels.
Ancient Chinese glass refers to all types of glass manufactured in China prior to the Qing dynasty (1644–1911). In Chinese history, glass played a peripheral role in arts and crafts, when compared to ceramics and metal work. The limited archaeological distribution and use of glass objects are evidence of the rarity of the material. Literary sources date the first manufacture of glass to the 5th century AD. However, the earliest archaeological evidence for glass manufacture in China comes from the Warring States period.
Forest glass is late medieval glass produced in northwestern and central Europe from approximately 1000–1700 AD using wood ash and sand as the main raw materials and made in factories known as glasshouses in forest areas. It is characterized by a variety of greenish-yellow colors, the earlier products often being of crude design and poor quality, and was used mainly for everyday vessels and increasingly for ecclesiastical stained glass windows. Its composition and manufacture contrast sharply with Roman and pre-Roman glassmaking centered on the Mediterranean and contemporaneous Byzantine and Islamic glass making to the east.
Oxhide ingots are heavy (20–30 kg) metal slabs, usually of copper but sometimes of tin, produced and widely distributed during the Mediterranean Late Bronze Age (LBA). Their shape resembles the hide of an ox with a protruding handle in each of the ingot’s four corners. Early thought was that each ingot was equivalent to the value of one ox. However, the similarity in shape is simply a coincidence. The ingots' producers probably designed these protrusions to make the ingots easily transportable overland on the backs of pack animals. Complete or partial oxhide ingots have been discovered in Sardinia, Crete, Peloponnese, Cyprus, Cannatello in Sicily, Boğazköy in Turkey, Qantir in Egypt, and Sozopol in Bulgaria. Archaeologists have recovered many oxhide ingots from two shipwrecks off the coast of Turkey.
Hellenistic glass was glass produced during the Hellenistic period in the Mediterranean, Europe, western Asia and northern Africa. Glassmaking at this time was based on the technological traditions of the Classical antiquity and the Late Bronze Age, but was marked by transition from limited production of luxury objects made for the social elite to mass production of affordable glass vessels used by the broader public to satisfy everyday needs.
Robert Brill is an American archaeologist, best known for his work on the chemical analysis of ancient glass. Born in the US in 1929, Brill attended West Side High School in Newark, New Jersey, before going on to study for his B.S. degree at Upsala College. Having completed his Ph.D. in physical chemistry at Rutgers University in 1954, Brill returned to Upsala College to teach chemistry. In 1960, he joined the staff of the Corning Museum of Glass as their second research scientist.
Islamic glass is glass made in the Islamic world, especially in periods up to the 19th century. It built on pre-Islamic cultures in the Middle East, especially ancient Egyptian, Persian and Roman glass, and developed distinct styles, characterized by the introduction of new techniques and the reinterpreting of old traditions. It came under European influence by the end of the Middle Ages, with imports of Venetian glass documented by the late 15th century.
Medieval stained glass is the coloured and painted glass of medieval Europe from the 10th century to the 16th century. For much of this period stained glass windows were the major pictorial art form, particularly in northern France, Germany and England, where windows tended to be larger than in southern Europe. In some countries, such as Sweden and England, only a small number of original stained windows has survived to this day.
Ceramic petrography is a laboratory-based scientific archaeological technique that examines the mineralogical and microstructural composition of ceramics and other inorganic materials under the polarised light microscope in order to interpret aspects of the provenance and technology of artefacts.
The history of glass-making dates back to at least 3,600 years ago in Mesopotamia. However, most writers claim that they may have been producing copies of glass objects from Egypt. Other archaeological evidence suggests that the first true glass was made in coastal north Syria, Mesopotamia or Egypt. The earliest known glass objects, of the mid 2,000 BCE, were beads, perhaps initially created as the accidental by-products of metal-working (slags) or during the production of faience, a pre-glass vitreous material made by a process similar to glazing. Glass products remained a luxury until the disasters that overtook the late Bronze Age civilizations seemingly brought glass-making to a halt.
Due to various differences in cultural histories and environmental resources, West African nations developed glass traditions distinct from Egypt, North Africa and the rest of the world. The presence of glass in Sub-Saharan Africa mostly consists of the importation of glass beads shipped primarily from the Middle East and India as early as 200-300AD; later, from Portugal, the Netherlands, and Venice.
Gao-Saney, also spelled Gao-Sane, is an archaeological site near Gao in Mali. It was almost certainly the town known in historical accounts as Sarneh.
The Philippines is an archipelago located in Southeast Asia and consists of 7,641 islands. Prehistoric beads are among the most significant resources deriving from the human past. They are artifacts that inform individuals about archaeological records. Beads play a vital role in Asian lives, since they were utilized as human markers to indicate a territory; moreover, prehistoric beads were significant for ancestors as well as the people who occupied the identical territory. For instance, if beads are perished or destroyed, they can be recovered archaeologically due to their durability, which allows for the preservation of these resources. Furthermore, several of the decorative pieces and tools that they possess, as well as their culture, seem to reflect this maritime characteristic. Due to the fact that beads are transportable, compact in size, and appealing to the eye, they can essentially be discovered all over the world. Tools such as choppers made of shells as well as decorative pieces like shell beads are common in Southeast Asian archaeological records due to this characteristic. Various sites have been found to contain shell beads, including Sucgang Barrio in Bohol; Sibale Island, near Surigao; Suluan island, south of Samar; Lagen Island in Palawan; and Camotes Islands.
Khao Sam Kaeo is an archaeological site in Thailand's Chumphon province. It is located in Na Cha-ang subdistrict of Mueang Chumphon district, just north of the town of Chumphon, on the east coast of the Malay Peninsula, at the Kra Isthmus. Dated 400–100 BCE, Khao Sam Kaeo served as an extremely important port, as well as a crossroads for Asian connection and interaction, as it sat between the cultural regions of the South China Sea and the Bay of Bengal. There is evidence that material had come from the South China Sea, the Philippines, and Taiwan—all part of the maritime silk road of the time—proving the important technological and cultural connections between the site and these locations. This not only reveals the fact that people from across Asia ended up in Khao Sam Kaeo, but it also supports the idea that there was a transfer of ideas. When reviewing the material culture found at Khao Sam Kaeo, the transfer of ideas and trans-Asian connection becomes abundantly clear, especially when looking at ceramics, stone adzes, pendants, and jewelry. Data and research also point to the idea that foreign craftsmen stayed for long periods of time at Khao Sam Kaeo. Pottery and stone works made in an Indian technical style yet supposedly made locally support this idea. Collectively, evidence regarding material culture, raw materials, and biological data support the idea that the connections made at Khao Sam Kaeo were more than just trade and diffusion.
The Cardamom Mountains jar burials are a collection of twelve mortuary sites dating back to the late and post-Angkor period located in the Eastern region of Cambodia's Cardamom Mountains. In recent years, these sites have gained interest due to their unique wooden coffins and vast collections of large, ceramic jars that often hold multiple human skeletons. These remains encompass both adolescents and adults who are speculated to be from the highland populations that inhabited Cambodia's mountain range. Various types of grave goods have also been discovered inside and around these burial jars including glass beads, ceramics, and metal jewelry from maritime trade across South and Southeast Asia.