Roman glass

[1] This was a direct result of the massive growth of the Roman influence at the end of the Republican period, the Pax Romana that followed the decades of civil war,[4] and the stabilisation of the state that occurred under Augustus' rule.

[1] As a result of these factors, the cost of production was reduced and glass became available for a wider section of society in a growing variety of forms.

[1] The changes that took place in the Roman glass industry during this period can therefore be seen as a result of three primary influences: historical events, technical innovation and contemporary fashions.

[1] From the 2nd century onwards styles became increasingly regionalised,[1] and evidence indicates that bottles and closed vessels such as unguentaria moved as a by-product of the trade in their contents, and many appear to have matched the Roman scale of liquid measurement.

The movement of the capital to Constantinople rejuvenated the Eastern glass industry, and the presence of the Roman military in the western provinces did much to prevent any downturn there.

[10] This is thought to have originated either in the addition of salt (NaCl) to reduce the melting temperature and viscosity of the glass, or as a contaminant in the natron.

The siting of glass-making workshops was governed by three primary factors: the availability of fuel which was needed in large quantities, sources of sand which represented the major constituent of the glass, and natron to act as a flux.

[11] This facilitated the trade in the raw colourless or naturally coloured glass which they produced, which reached glass-working sites across the Roman empire.

Italy is known to have been a centre for the working and export of brightly coloured vessels at this time,[21] with production peaking during the mid-1st century AD.

[25] Glass working sites such as those at Aquileia also had an important role in the spread of glassworking traditions[23] and the trade in materials that used hollow glasswares as containers.

During the late Republican period new highly coloured striped wares with a fusion of dozens of monochrome and lace-work strips were introduced.

[8] These objects also represent the first with a distinctly Roman style unrelated to the Hellenistic casting traditions on which they are based, and are characterised by novel rich colours.

[8] Of these, Emerald green and peacock blue were new colours introduced by the Romano-Italian industry and almost exclusively associated with the production of fine wares.

[8] However, during the last thirty years of the 1st century AD there was a marked change in style, with strong colours disappearing rapidly, replaced by 'aqua' and true colourless glasses.

[8] Debate continues whether this change in fashion indicates a change in attitude that placed glass as individual material of merit no longer required to imitate precious stones, ceramics, or metal,[7] or whether the shift to colourless glass indicated an attempt to mimic highly prized rock crystal.

[1] Pliny's Natural History states that "the most highly valued glass is colourless and transparent, as closely as possible resembling rock crystal" (36, 198), which is thought to support this last position, as is evidence for the persistence of casting as a production technique, which produced the thickly walled vessels necessary to take the pressure of extensive cutting and polishing associated with crystal working.

There are a very fewer larger designs, but the great majority of the around 500 survivals are roundels that are the cut-off bottoms of wine cups or glasses used to mark and decorate graves in the Catacombs of Rome by pressing them into the mortar.

In contrast, a much smaller group of 3rd century portrait levels are superbly executed, with pigment painted on top of the gold.

[1] The earliest panes were rough cast into a wooden frame on top of a layer of sand or stone,[1] but from the late 3rd century onwards window glass was made by the muff process, where a blown cylinder was cut laterally and flattened out to produce a sheet.

These colours formed the basis of all Roman glass, and although some of them required high technical ability and knowledge, a degree of uniformity was achieved.

The diffraction of light by the so-formed grating constituted by hundred of nanolayers of silica crystallised at the surface of the altered glass is responsible for a typical golden patina.

Cage cup from Cologne , dated to the mid-4th century. Collection Staatliche Antikensammlung , Munich
This pyxis is exemplary of luxury Roman glassware, c. late 1st century BC. Walters Art Museum , Baltimore
Roman glass from the 2nd century
Enamelled glass depicting a gladiator , found at Begram , Afghanistan , which was once part of the Greco-Bactrian Kingdom , but was ruled by the Kushan Empire during the contemporaneous Roman Principate period, to which the glass belongs, 52–125 AD (although there is some scholarly debate about the precise dating). [ 3 ]
A double-handled glass vial from Syria, c. 4th century AD
"Circus beaker" from Roman Iron Age , found in Varpelev, Denmark
Green Roman glass cup unearthed from an Eastern Han Dynasty (25–220 AD) tomb, Guangxi , China
Close-up of beach sand, the main component of Roman glass
Roman blown-glass cinerary urn , dated between 1st and 3rd centuries AD
Cameo glass plaque with the infant Bacchus and a satyr , early 1st century AD.
Engraved glass bowl from Colonia Agrippina, 3rd century AD
The Cologne cage cup, 12 cm high, 4th century
Glass vessel from the 2nd century AD, found in Bosanski Novi
The Portland Vase , 5–25 AD(?) cameo glass .
Ribbed bowl of mosaic glass in the Metropolitan Museum of Art
The Lycurgus Cup , a dichroic (colour-changing) cage cup , lit from behind, with a modern foot and rim.
Detail of a gold glass medallion with a portrait of a family, from Alexandria ( Roman Egypt ), 3rd–4th century ( Brescia , Museo di Santa Giulia ) [ 26 ]