History of glass

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 east 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 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.
Development of glass technology in India may have begun in 1,730 BCE.
From across the former Roman Empire, archaeologists have recovered glass objects that were used in domestic, industrial and funerary contexts. 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.

Origins

Naturally occurring glass, especially the volcanic glass obsidian, has been used by many Stone Age societies across the globe for the production of sharp cutting tools and, due to its limited source areas, was extensively traded. But in general, archaeological evidence suggests that the first true glass was made in coastal north Syria, Mesopotamia or ancient Egypt.
A lump of glass was found at Eridu in Iraq that can be dated to the twenty-first century BCE or even earlier; it was produced during the Akkadian Empire or the early Ur III period. The glass is of blue colour, which was achieved with cobalt. Such glass is generally known as Egyptian blue, but the technique was attested in Eridu long before it emerged in Egypt.
Because of Egypt's favorable environment for preservation, the majority of well-studied early glass is found there, although some of this is likely to have been imported. The earliest known glass objects, of the mid-third millennium BCE, were beads, perhaps initially created as accidental by-products of metal-working or during the production of faience, a pre-glass vitreous material made by a process similar to glazing.
During the Late Bronze Age in Egypt and Western Asia, there was a rapid growth in glassmaking technology. Archaeological finds from this period include colored glass ingots, vessels and the ubiquitous beads. The alkali of Syrian and Egyptian glass was soda ash, which can be extracted from the ashes of many plants, notably halophile seashore plants like saltwort. The latest vessels were 'core-formed', produced by winding a ductile rope of glass around a shaped core of sand and clay over a metal rod, then fusing it by reheating it several times.
Threads of thin glass of different colors made with admixtures of oxides were subsequently wound around these to create patterns, which could be drawn into festoons by using metal raking tools. The vessel would then be rolled smooth on a slab in order to press the decorative threads into its body. Handles and feet were applied separately. The rod was subsequently allowed to cool as the glass slowly annealed and was eventually removed from the center of the vessel, after which the core material was scraped out. Glass shapes for inlays were also often created in moulds. Much of early glass production, however, relied on grinding techniques borrowed from stone working. This meant that the glass was ground and carved in a cold state.
By the 15th century BCE, extensive glass production was occurring in Western Asia, Crete, and Egypt; and the Mycenaean Greek term ??????, ku-wa-no-wo-ko-i, meaning "workers of lapis lazuli and glass" is attested.
It is thought that the techniques and recipes required for the initial fusing of glass from raw materials were a closely guarded technological secret reserved for the large palace industries of powerful states. Glass workers in other areas therefore relied on imports of preformed glass, often in the form of cast ingots such as those found on the Ulu Burun shipwreck off the coast of modern Turkey.
File:Lubaczów Goblet with coats of arms.jpg|thumb|An early 18th-century goblet with coats of arms in the District Museum in Tarnów is one of the highest preserved examples of artistry of less known Lubaczów glass manufacturing factory. The goblet was almost entirely covered with a pattern of so-called carp scales and hand-engraved decoration.
Glass remained a luxury material, and the disasters that overtook Late Bronze Age civilizations seemed to have brought glass-making to a halt. It picked up again in its former sites, Syria and Cyprus, in the 9th century BCE, when the techniques for making colorless glass were discovered.
The first glassmaking "manual" dates back to ca. 650 BCE. Instructions on how to make glass are contained in cuneiform tablets discovered in the library of the Assyrian king Ashurbanipal.
In Egypt, glass-making did not revive until it was reintroduced in Ptolemaic Alexandria. Core-formed vessels and beads were still widely produced, but other techniques came to the fore with experimentation and technological advancements.
During the Hellenistic period many new techniques of glass production were introduced and glass began to be used to make larger pieces, notably table wares. Techniques developed during this period include 'slumping' viscous glass over a mould in order to form a dish and 'millefiori' technique, where canes of multicolored glass were sliced and the slices arranged together and fused in a mould to create a mosaic-like effect. It was also during this period that colorless or decolored glass began to be prized and methods for achieving this effect were investigated more fully.
According to Pliny the Elder, Phoenician traders were the first to stumble upon glass manufacturing techniques at the site of the Belus River. Georgius Agricola, in De re metallica, reported a traditional serendipitous "discovery" tale of familiar type:

The tradition is that a merchant ship laden with nitrum being moored at this place, the merchants were preparing their meal on the beach, and not having stones to prop up their pots, they used lumps of nitrum from the ship, which fused and mixed with the sands of the shore, and there flowed streams of a new translucent liquid, and thus was the origin of glass.

This account is more a reflection of Roman experience of glass production, however, as white silica sand from this area was used in the production of glass within the Roman Empire due to its high purity levels. During the 1st century BCE, glass blowing was discovered on the Syro-Judean coast, revolutionizing the industry. The first evidence of the invention of glassblowing was found in the Jewish Quarter of Jerusalem, in a layer of fill inside a ritual bath that was overlain with the paving stones of the Herodian street. Several other site of producing "Judean Glass" were found in Galilee. Glass vessels were now inexpensive compared to pottery vessels. Growth of the use of glass products occurred throughout the Roman world. Glass became the Roman plastic, and glass containers produced in Alexandria spread throughout the Roman Empire. With the discovery of clear glass, by glass blowers in Alexandria circa 100 CE, the Romans began to use glass for architectural purposes. Cast glass windows, albeit with poor optical qualities, began to appear in the most important buildings in Rome and the most luxurious villas of Herculaneum and Pompeii. Over the next 1,000 years, glass making and working continued and spread through southern Europe and beyond.

History by culture

Iran

The first Persian glass comes in the form of beads dating to the late Bronze Age, and was discovered during the explorations of Dinkhah Tepe in Iranian by Charles Burney. Glass tubes were discovered by French archaeologists at Chogha Zanbil, belonging to the middle Elamite period. Mosaic glass cups have also been found at Teppe Hasanlu and Marlik Tepe in northern Iran, dating to the Iron Age. These cups resemble ones from Mesopotamia, as do cups found in Susa during the late Elamite period.
Glass tubes containing kohl have also been found in Iranian, belonging to the Achaemenid period. During this time, glass vessels were usually plain and colorless. By the Seleucid and late Parthian era, Greek and Roman techniques were prevalent. During the Sasanian period, glass vessels were decorated with local motifs.

Levant and Anatolia

A glassmaking crucible was discovered at Alalakh in the Amuq Valley of Turkey during the excavation seasons 2011–2014. This is the earliest evidence for glassmaking in the Syro-Levantine zone – the area which became famous for glassmaking later on. This material is "contemporary with, or even slightly earlier" than the fourteenth-century BC dates from Egypt.
The discovery provides the earliest evidence for Late Bronze Age glassmaking outside of Egypt and the central Mesopotamia.
This production area may be associated with the Kingdom of Mitanni. According to the authors, this geographical area can be linked to the descriptions of glassmaking in cuneiform tablets, which provides some additional historical context.
A glass bottle fragment from Büklükale, in central Turkey, is estimated to be around 1600 BC old. This may represent the oldest glass work in Anatolia. The fragment is from the Hittite Empire period. It is unusually large compared to other glass bottles from Mesopotamia at the time. A production centre of glass may have existed in this area of Anatolia.

India

Evidence of glass during the Chalcolithic has been found in Hastinapur, India. The earliest glass item from the Indus Valley civilization is a brown glass bead found at Harappa, dating to 1700 BCE. This makes it the earliest evidence of glass in South Asia. Glass discovered from later sites dating from 600 to 300 BCE displays common colors.
Texts such as the Shatapatha Brahmana and Vinaya Pitaka mention glass, implying they could have been known in India during the early first millennium BCE. Glass objects have also been found at Beed, Sirkap and Sirsukh, all dating to around the 5th century BCE. However, the first unmistakable evidence for widespread glass usage comes from the ruins of Taxila, where bangles, beads, small vessels, and tiles were discovered in large quantities. These glassmaking techniques may have been transmitted from cultures in Western Asia.
The site of Kopia, in Uttar Pradesh, is the first site in India to locally manufacture glass, with items dating between the 7th century BCE to the 2nd century CE. Early Indian glass of this period was likely made locally, as they differ significantly in chemical composition when compared to Babylonian, Roman and Chinese glass.
By the 1st century AD, glass was being used for ornaments and casing in South Asia. Contact with the Greco-Roman world added newer techniques, and Indians artisans mastered several techniques of glass molding, decorating and coloring by the succeeding centuries. The Satavahana period of India also produced short cylinders of composite glass, including those displaying a lemon yellow matrix covered with green glass.