The discovery of glass
Natural glass has existed since the beginnings of time, formed when certain types of rocks melt as a result of high-temperature phenomena such as volcanic eruptions, lightning strikes or the impact of meteorites, and then cool and solidify rapidly. Stone-age man is believed to have used cutting tools made of obsidian (a natural glass of volcanic origin also known as hyalopsite, Iceland agate, or mountain mahogany) and tektites (naturally-formed glasses of extraterrestrial or other origin, also referred to as obsidianites).
According to the ancient-Roman historian Pliny (AD 23-79), Phoenician merchants transporting stone actually discovered glass (or rather became aware of its existence accidentally) in the region of Syria around 5000 BC. Pliny tells how the merchants, after landing, rested cooking pots on blocks of nitrate placed by their fire. With the intense heat of the fire, the blocks eventually melted and mixed with the sand of the beach to form an opaque liquid.
This brief history looks, however, at the origins and evolution of man-made glass.
5000 BC - A craft is born
The earliest man-made glass objects, mainly non-transparent glass beads, are thought to date back to around 3500 BC, with finds in Egypt and Eastern Mesopotamia. In the third millennium, in central Mesopotamia, the basic raw materials of glass were being used principally to produce glazes on pots and vases. The discovery may have been coincidental, with calciferous sand finding its way into an overheated kiln and combining with soda to form a coloured glaze on the ceramics. It was then, above all, Phoenician merchants and sailors who spread this new art along the coasts of the Mediterranean.
3500 BC - The oldest fragments of glass vases (evidence of the origins of the hollow glass industry), however, date back to the 16th century BC and were found in Mesopotamia. Hollow glass production was also evolving around this time in Egypt, and there is evidence of other ancient glassmaking activities emerging independently in Mycenae (Greece), China and North Tyrol.
16th century BC - Early hollow glass production
After 1500 BC, Egyptian craftsmen are known to have begun developing a method for producing glass pots by dipping a core mould of compacted sand into molten glass and then turning the mould so that molten glass adhered to it. While still soft, the glass-covered mould could then be rolled on a slab of stone in order to smooth or decorate it. The earliest examples of Egyptian glassware are three vases bearing the name of the Pharaoh Thoutmosis III (1504-1450 BC), who brought glassmakers to Egypt as prisoners following a successful military campaign in Asia.
1500 BC - There is little evidence of further evolution until the 9th century BC, when glassmaking revived in Mesopotamia. Over the following 500 years, glass production centred on Alessandria, from where it is thought to have spread to Italy.
9th century BC - The first glassmaking "manual" dates back to around 650 BC. Instructions on how to make glass are contained in tablets from the library of the Assyrian king Ashurbanipal (669-626 BC).
650 BC - Starting to blow
A major breakthrough in glassmaking was the discovery of glassblowing some time between 27 BC and AD 14, attributed to Syrian craftsmen from the Sidon-Babylon area. The long thin metal tube used in the blowing process has changed very little since then. In the last century BC, the ancient Romans then began blowing glass inside moulds, greatly increasing the variety of shapes possible for hollow glass items.
27 BC-AD 14 - The Roman connection
The Romans also did much to spread glassmaking technology. With its conquests, trade relations, road building, and effective political and economical administration, the Roman Empire created the conditions for the flourishing of glassworks across western Europe and the Mediterranean.