![Roman - Pyxis - Walters 4776 - View A (cropped)](https://upload.wikimedia.org/wikipedia/commons/3/3f/Roman_-_Pyxis_-_Walters_4776_-_View_A_%28cropped%29.jpg)
Roman glass objects have been recovered across the
Roman Empire
The Roman Empire ( la, Imperium Romanum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post-Republican period of ancient Rome. As a polity, it included large territorial holdings around the Mediterr ...
in domestic, industrial and
funerary
A funeral is a ceremony connected with the Disposal of human corpses, final disposition of a corpse, such as a burial or cremation, with the attendant observances. Funerary customs comprise the complex of beliefs and practices used by a culture ...
contexts.
Glass
Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of ...
was used primarily for the production of vessels, although mosaic tiles and window glass were also produced. Roman glass production developed from
Hellenistic
In Classical antiquity, the Hellenistic period covers the time in Mediterranean history after Classical Greece, between the death of Alexander the Great in 323 BC and the emergence of the Roman Empire, as signified by the Battle of Actium in ...
technical traditions, initially concentrating on the production of intensely coloured cast glass vessels. However, during the 1st century AD the industry underwent rapid technical growth that saw the introduction of
glass blowing
Glassblowing is a glassforming technique that involves inflating molten glass into a bubble (or parison) with the aid of a blowpipe (or blow tube). A person who blows glass is called a ''glassblower'', ''glassmith'', or ''gaffer''. A '' lampworke ...
and the dominance of colourless or 'aqua' glasses. Production of raw glass was undertaken in geographically separate locations to the working of glass into finished vessels,
[Fleming, S. J., 1999. ''Roman Glass; reflections on cultural change''. Philadelphia, University of Pennsylvania Museum of Archaeology and Anthropology.][Stern, E. M., 1999. Roman Glassblowing in a Cultural Context. ''American Journal of Archaeology'' 103/3, 441–484.] and by the end of the 1st century AD large scale manufacturing resulted in the establishment of glass as a commonly available material in the Roman world, and one which also had technically very difficult specialized types of luxury glass, which must have been very expensive.
Growth of the Roman glass industry
![Gladiateur Begram Guimet 18117](https://upload.wikimedia.org/wikipedia/commons/d/df/Gladiateur_Begram_Guimet_18117.jpg)
Despite the growth of
glass working in the Hellenistic World and the growing place of glass in
material culture
Material culture is the aspect of social reality grounded in the objects and architecture that surround people. It includes the usage, consumption, creation, and trade of objects as well as the behaviors, norms, and rituals that the objects creat ...
, at the beginning of the 1st century AD there was still no Latin word for it in the Roman world.
However, glass was being produced in Roman contexts using primarily
Hellenistic
In Classical antiquity, the Hellenistic period covers the time in Mediterranean history after Classical Greece, between the death of Alexander the Great in 323 BC and the emergence of the Roman Empire, as signified by the Battle of Actium in ...
techniques and styles (see
glass, history) by the late
Republican
Republican can refer to:
Political ideology
* An advocate of a republic, a type of government that is not a monarchy or dictatorship, and is usually associated with the rule of law.
** Republicanism, the ideology in support of republics or agains ...
period. The majority of manufacturing techniques were time-consuming, and the initial product was a thick-walled vessel which required considerable finishing. This, combined with the cost of importing
natron
Natron is a naturally occurring mixture of sodium carbonate decahydrate ( Na2CO3·10H2O, a kind of soda ash) and around 17% sodium bicarbonate (also called baking soda, NaHCO3) along with small quantities of sodium chloride and sodium sulfate. N ...
for the production of raw glass, contributed to the limited use of glass and its position as an expensive and high-status material.
![Double-handled vial Louvre MND1503](https://upload.wikimedia.org/wikipedia/commons/6/69/Double-handled_vial_Louvre_MND1503.jpg)
The glass industry was therefore a relatively minor craft during the Republican period; although, during the early decades of the 1st century AD the quantity and diversity of glass vessels available increased dramatically.
This was a direct result of the massive growth of the Roman influence at the end of the Republican period, the
Pax Romana
The Pax Romana (Latin for 'Roman peace') is a roughly 200-year-long timespan of Roman history which is periodization, identified as a period and as a golden age (metaphor), golden age of increased as well as sustained Imperial cult of ancient Rome ...
that followed the decades of civil war,
[Dussart, O., B. Velde, et al., 2004. Glass from Qal'at Sem'an (Northern Syria): The reworking of glass during the transition from Roman to Islamic compositions. ''Journal of Glass Studies'' 46, 67–83.] and the stabilisation of the state that occurred under
Augustus
Caesar Augustus (born Gaius Octavius; 23 September 63 BC – 19 August AD 14), also known as Octavian, was the first Roman emperor; he reigned from 27 BC until his death in AD 14. He is known for being the founder of the Roman Pri ...
' rule.
Still, Roman glasswares were already making their way from
Western Asia
Western Asia, West Asia, or Southwest Asia, is the westernmost subregion of the larger geographical region of Asia, as defined by some academics, UN bodies and other institutions. It is almost entirely a part of the Middle East, and includes Ana ...
(i.e. the
Parthian Empire
The Parthian Empire (), also known as the Arsacid Empire (), was a major Iranian political and cultural power in ancient Iran from 247 BC to 224 AD. Its latter name comes from its founder, Arsaces I, who led the Parni tribe in conque ...
) to the
Kushan Empire
The Kushan Empire ( grc, Βασιλεία Κοσσανῶν; xbc, Κυϸανο, ; sa, कुषाण वंश; Brahmi: , '; BHS: ; xpr, 𐭊𐭅𐭔𐭍 𐭇𐭔𐭕𐭓, ; zh, 貴霜 ) was a syncretic empire, formed by the Yuezhi, i ...
in Afghanistan and India and as far as the
Han Empire
The Han dynasty (, ; ) was an imperial dynasty of China (202 BC – 9 AD, 25–220 AD), established by Liu Bang (Emperor Gao) and ruled by the House of Liu. The dynasty was preceded by the short-lived Qin dynasty (221–207 BC) and a warr ...
of
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
. The
first Roman glass found in China came from
an early 1st-century BC tomb at
Guangzhou
Guangzhou (, ; ; or ; ), also known as Canton () and alternatively romanized as Kwongchow or Kwangchow, is the capital and largest city of Guangdong province in southern China. Located on the Pearl River about north-northwest of Hong Kon ...
, ostensibly via the
South China Sea
The South China Sea is a marginal sea of the Western Pacific Ocean. It is bounded in the north by the shores of South China (hence the name), in the west by the Indochinese Peninsula, in the east by the islands of Taiwan and northwestern Phil ...
.
In addition to this a major new technique in glass production had been introduced during the 1st century AD.
[Allen, D., 1998. ''Roman Glass in Britain''. Princes Risborough, Buckinghamshire, Shire Publications.] Glassblowing
Glassblowing is a glassforming technique that involves inflating molten glass into a bubble (or parison) with the aid of a Blowpipe (tool), blowpipe (or blow tube). A person who blows glass is called a ''glassblower'', ''glassmith'', or ''gaffer'' ...
allowed glass workers to produce vessels with considerably thinner walls, decreasing the amount of glass needed for each vessel. Glass blowing was also considerably quicker than other techniques, and vessels required considerably less finishing, representing a further saving in time, raw material and equipment. Although earlier techniques dominated during the early Augustan and
Julio-Claudian
, native_name_lang=Latin, coat of arms=Great_Cameo_of_France-removebg.png, image_size=260px, caption= The Great Cameo of France depicting emperors Augustus, Tiberius, Claudius and Nero, type=Ancient Roman dynasty, country= Roman Empire, estates=* ...
periods,
[Grose, D. F., 1991. Early Imperial Roman cast glass: The translucent coloured and colourless fine wares. ''Roman Glass: two centuries of art and invention''. M. Newby and K. Painter. London: Society of Antiquaries of London.] by the middle to late 1st century AD earlier techniques had been largely abandoned in favour of blowing.
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. By the mid-1st century AD this meant that glass vessels had moved from a valuable, high-status commodity, to a material commonly available: "a
lass
Lass may refer to:
*A girl/young woman in Scottish/Northern English
People Surname
*August Lass (1903–1962), Estonian footballer
* Barbara Kwiatkowska-Lass (1940–1995), Polish actress
*Donna Lass (1944–' 1970), possible victim of the Zodiac ...
drinking cup could be bought for a copper coin" (Strabo,
Geographica
The ''Geographica'' (Ancient Greek: Γεωγραφικά ''Geōgraphiká''), or ''Geography'', is an encyclopedia of geographical knowledge, consisting of 17 'books', written in Ancient Greek, Greek and attributed to Strabo, an educated citizen ...
XVI.2). This growth also saw the production of the first glass
tesserae
A tessera (plural: tesserae, diminutive ''tessella'') is an individual tile, usually formed in the shape of a square, used in creating a mosaic. It is also known as an abaciscus or abaculus.
Historical tesserae
The oldest known tesserae ...
for mosaics, and the first window glass,
as furnace technology improved allowing molten glass to be produced for the first time.
[Stern, E. M., 1995. ''Roman Mould-blown Glass''. Rome, Italy, L'Erma di Fretshneidur in association with the Toledo Museum of Art.] At the same time, the expansion of the empire also brought an influx of people and an expansion of cultural influences that resulted in the adoption of eastern decorative styles.
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.
They are also linked to the fashions and technologies developed in the
ceramic
A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain ...
trade, from which a number of forms and techniques were drawn.
![Green glass Roman cup unearthed at Eastern Han tomb, Guixian, China](https://upload.wikimedia.org/wikipedia/commons/f/f8/Green_glass_Roman_cup_unearthed_at_Eastern_Han_tomb%2C_Guixian%2C_China.jpg)
Glass making reached its peak at the beginning of the 2nd century AD, with glass objects in domestic contexts of every kind.
The primary production techniques of blowing, and to a lesser extent casting, remained in use for the rest of the Roman period, with changes in vessel types but little change in technology.
From the 2nd century onwards styles became increasingly regionalised,
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 use of coloured glass as a decorative addition to pale and colourless glasses also increased, and metal vessels continued to influence the shape of glass vessels.
After the conversion of Constantine, glass works began to move more quickly from depicting Pagan religious imagery towards Christian religious imagery. The movement of the capital to
Constantinople
la, Constantinopolis ota, قسطنطينيه
, alternate_name = Byzantion (earlier Greek name), Nova Roma ("New Rome"), Miklagard/Miklagarth (Old Norse), Tsargrad ( Slavic), Qustantiniya (Arabic), Basileuousa ("Queen of Cities"), Megalopolis (" ...
rejuvenated the Eastern glass industry, and the presence of the
Roman military
The military of ancient Rome, according to Titus Livius, one of the more illustrious historians of Rome over the centuries, was a key element in the rise of Rome over "above seven hundred years" from a small settlement in Latium to the capital of ...
in the western provinces did much to prevent any downturn there.
By the mid-4th century mould-blowing was in use only sporadically.
Production
Composition
Roman glass production relied on the application of heat to fuse two primary ingredients: silica and soda.
Technical studies of archaeological glasses divide the ingredients of glass as formers, fluxes, stabilisers, as well as possible opacifiers or colourants.
*Former: The major component of the glass is silica, which during the Roman period was
sand
Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of s ...
(quartz), which contains some
alumina (typically 2.5%) and nearly 8%
lime
Lime commonly refers to:
* Lime (fruit), a green citrus fruit
* Lime (material), inorganic materials containing calcium, usually calcium oxide or calcium hydroxide
* Lime (color), a color between yellow and green
Lime may also refer to:
Botany ...
.
Alumina contents vary, peaking around 3% in glasses from the
western Empire
The Western Roman Empire comprised the western provinces of the Roman Empire at any time during which they were administered by a separate independent Imperial court; in particular, this term is used in historiography to describe the period fr ...
, and remaining notably lower in glasses from the Middle East.
*Flux: This ingredient was used to lower the
melting point
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends ...
of the silica to form glass. Analysis of Roman glass has shown that soda (
sodium carbonate
Sodium carbonate, , (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions ...
) was used exclusively in glass production.
[Stern, W. B., 1990. The composition of Roman glass. ''Annales du 11e Congres''. Amsterdam.] During this period, the primary source of soda was
natron
Natron is a naturally occurring mixture of sodium carbonate decahydrate ( Na2CO3·10H2O, a kind of soda ash) and around 17% sodium bicarbonate (also called baking soda, NaHCO3) along with small quantities of sodium chloride and sodium sulfate. N ...
, a naturally occurring salt found in dry lake beds. The main source of natron during the Roman period was
Wadi El Natrun
Wadi El Natrun (Arabic: "Valley of Natron"; Coptic: , "measure of the hearts") is a depression in northern Egypt that is located below sea level and below the Nile River level. The valley contains several alkaline lakes, natron-rich salt dep ...
, Egypt, although there may have been a source in Italy.
*Stabiliser: Glasses formed of silica and soda are naturally soluble, and require the addition of a stabiliser such as lime or magnesia. Lime was the primary stabiliser in use during the Roman period, entering the glass through
calcareous
Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.
In zoology
''Calcareous'' is used as an adje ...
particles in the beach sand, rather than as a separate component.
Roman glass has also been shown to contain around 1% to 2% chlorine, in contrast to later glasses.
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.
Glass making
![Urna cineraria romana de vidrio (M](https://upload.wikimedia.org/wikipedia/commons/0/0d/Urna_cineraria_romana_de_vidrio_%28M.A.N._Inv.1990-69-150%29_01.jpg)
Archaeological evidence for glass making during the Roman period is scarce, but by drawing comparisons with the later
Islamic
Islam (; ar, ۘالِإسلَام, , ) is an Abrahamic monotheistic religion centred primarily around the Quran, a religious text considered by Muslims to be the direct word of God (or '' Allah'') as it was revealed to Muhammad, the mai ...
and
Byzantine
The Byzantine Empire, also referred to as the Eastern Roman Empire or Byzantium, was the continuation of the Roman Empire primarily in its eastern provinces during Late Antiquity and the Middle Ages, when its capital city was Constantinopl ...
periods, it is clear that glass making was a significant industry. By the end of the Roman period glass was being produced in large quantities contained in tanks situated inside highly specialised furnaces, as the 8-tonne glass slab recovered from
Bet She'arim illustrates.
These workshops could produce many tonnes of raw glass in a single furnace firing, and although this firing might have taken weeks, a single primary workshop could potentially supply multiple secondary glass working sites. It is therefore thought that raw glass production was centred around a relatively small number of workshops,
where glass was produced on a large scale and then broken into chunks.
[Freestone, I. C., M. Ponting, Hughes, M.J.,2002. Origins of Byzantine glass from Maroni Petrera, Cyprus. ''Archaeometry'' 44, 257–272.] There is only limited evidence for local glass making, and only in context of window glass.
The development of this large-scale industry is not fully understood, but
Pliny's Natural History
The ''Natural History'' ( la, Naturalis historia) is a work by Pliny the Elder. The largest single work to have survived from the Roman Empire to the modern day, the ''Natural History'' compiles information gleaned from other ancient authors. ...
(36, 194), in addition to evidence for the first use of molten glass in the mid-1st century AD,
indicates that furnace technologies experienced marked development during the early-to-mid-1st century AD, in tandem with the expansion of glass production.
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. Roman glass relied on natron from Wadi El Natrun, and as a result it is thought that glass-making workshops during the Roman period may have been confined to near-coastal regions of the eastern
Mediterranean
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the e ...
.
This facilitated the trade in the raw colourless or naturally coloured glass which they produced, which reached glass-working sites across the Roman empire.
The scarcity of archaeological evidence for Roman glass-making facilities has resulted in the use of chemical compositions as evidence for production models,
as the division of production indicates that any variation is related to differences in raw glass making.
However, the Roman reliance on natron from Wadi El Natrun as a flux,
[Jackson, C. M., H. E. M. Cool, Wager, E.C.W., 1998. The manufacture of glass in Roman York. ''Journal of Glass Studies'' 40, 55–61.] has resulted in a largely homogenous composition in the majority of Roman glasses.
[Velde, B., Year. Observations on the chemical compositions of several types of Gallo-Roman and Frankish glass production. In: ''9e Congres International d'Etude Historique du Verre'', Nancy, France: Editions du Centre de Publications de L'A.I.H.V.] Despite the publication of major analyses,
[Brill, R. H., 1999. ''Chemical Analyses of Early Glasses''. New York, Corning Museum of Glass.] comparisons of chemical analyses produced by different analytical methods have only recently been attempted,
[Baxter, M. J., H. E. M. Cool, Jackson, C.M., 2006. Comparing glass compositional analyses. ''Archaeometry'' 48/3, 399–414.] and although there is some variation in Roman glass compositions, meaningful compositional groups have been difficult to establish for this period.
[Freestone, I. C., 2006. Glass production in ]Late Antiquity
Late antiquity is the time of transition from classical antiquity to the Middle Ages, generally spanning the 3rd–7th century in Europe and adjacent areas bordering the Mediterranean Basin. The popularization of this periodization in English ha ...
and the Early Islamic period: a geochemical perspective. ''Geomaterials in Cultural Heritage'', Geological Society of London. Special publication 257: 201–216.
Recycling
![Satyr Bacchus Petit Palais ADUT00240](https://upload.wikimedia.org/wikipedia/commons/d/da/Satyr_Bacchus_Petit_Palais_ADUT00240.jpg)
The Roman writers
Statius
Publius Papinius Statius (Greek: Πόπλιος Παπίνιος Στάτιος; ; ) was a Greco-Roman poet of the 1st century CE. His surviving Latin poetry includes an epic in twelve books, the ''Thebaid''; a collection of occasional poetry, ...
and
Martial
Marcus Valerius Martialis (known in English as Martial ; March, between 38 and 41 AD – between 102 and 104 AD) was a Roman poet from Hispania (modern Spain) best known for his twelve books of ''Epigrams'', published in Rome between AD 86 and ...
both indicate that recycling broken glass was an important part of the glass industry, and this seems to be supported by the fact that only rarely are glass fragments of any size recovered from domestic sites of this period.
In the western empire there is evidence that recycling of broken glass was frequent and extensive,
and that quantities of broken glassware were concentrated at local sites prior to melting back into raw glass.
In the eastern empire, there is evidence of recycled Roman glass being used to glaze Parthian pottery. Compositionally, repeated recycling is visible via elevated levels of those metals used as colourants.
[Freestone, I. C., 2005. The provenance of ancient glass through compositional analysis. ''Materials Issues in Art and Archaeology 7''.]
Melting does not appear to have taken place in crucibles; rather, cooking pots appear to have been used for small scale operations. For larger work, large tanks or tank-like ceramic containers were utilised. In the largest cases, large furnaces were built to surround these tanks.
Glass working
In comparison to glass making, there is evidence for glass working in many locations across the empire. Unlike the making process, the working of glass required significantly lower temperatures and substantially less fuel. As a result of this and the expansion of the Empire, glass working sites developed in Rome, Campania and the Po Valley
by the end of the 1st century BC, producing the new blown vessels alongside cast vessels. Italy is known to have been a centre for the working and export of brightly coloured vessels at this time,
[ Price, J., 1990. A survey of the Hellenistic and early Roman vessel glass found on the Unexplored Mansion Site at Knossos in Crete. ''Annales du 11e Congres''. Amsterdam.] with production peaking during the mid-1st century AD.
By the early-to-mid-1st century AD, the growth of the Empire saw the establishment of glass working sites at locations along trade routes, with Cologne and other Rhineland centres becoming important glass working sites from the Imperial period,
and Syrian glass being exported as far as Italy.
During this period vessel forms varied between workshops, with areas such as the Rhineland and northern France producing distinctive forms which are not seen further south.
Growth in the industry continued into the 3rd century AD, when sites at the Colonia Claudia Agrippinensis appear to have experienced significant expansion,
[Caldera de Castro, M. d. P., 1990. Roman glass in southwest Spain. ''Annales du 11e Congres''. Amsterdam.] and by the 3rd and early 4th centuries producers north of the Alps were exporting down to the north of Italy and the transalpine regions.
[Facchini, G. M., 1990. Roman glass in an excavational context: Angere (VA). Annales du 11e Congres. Amsterdam.]
Glass working sites such as those at Aquileia also had an important role in the spread of glassworking traditions
and the trade in materials that used hollow glasswares as containers.
However, by the 4th
and 5th centuries
Italian glass workshops predominate.
Styles
The earliest Roman glass follows Hellenistic traditions and uses strongly coloured and 'mosaic' patterned glass. During the late Republican period new highly coloured striped wares with a fusion of dozens of monochrome and lace-work strips were introduced.
During this period there is some evidence that styles of glass varied geographically, with the translucent coloured fine wares of the early 1st century notably 'western' in origin, whilst the later colourless fine wares are more 'international'.
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.
'Emerald' green, dark or
cobalt blue
Cobalt blue is a blue pigment made by sintering cobalt(II) oxide with aluminum(III) oxide (alumina) at 1200 °C. Chemically, cobalt blue pigment is cobalt(II) oxide-aluminium oxide, or cobalt(II) aluminate, CoAl2O4. Cobalt blue is lighter ...
, a deep blue-green and Persian or 'peacock' blue are most commonly associated with this period, and other colours are very rare.
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.
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.
Colourless and 'aqua' glasses had been in use for vessels and some mosaic designs prior to this, but start to dominate the blown glass market at this time.
The use of strong colours in cast glass died out during this period, with colourless or 'aqua' glasses dominating the last class of cast vessels to be produced in quantity, as mould and free-blowing took over during the 1st century AD.
From around 70 AD colourless glass becomes the predominant material for fine wares, and the cheaper glasses move towards pale shades of blue, green, and yellow.
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,
or whether the shift to colourless glass indicated an attempt to mimic highly prized rock crystal.
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.
Vessel production techniques
Core and rod formed vessels
Artisans used a mass of mud and straw fixed around a metal rod to form a core, and built up a vessel by either dipping the core in liquified glass, or by trailing liquid glass over the core.
The core was removed after the glass had cooled, and handles, rims and bases were then added. These vessels are characterised by relatively thick walls, bright colours and zigzagging patterns of contrasting colours, and were limited in size to small
unguent
An unguent is a soothing preparation spread on wounds, burns, rashes, abrasions or other topical injuries (i.e. damage to the skin). It is similar to an ointment, though typically an unguent is oilier and less viscous. It is usually delivered as a ...
or scent containers.
This early technique continued in popularity during the 1st century BC,
despite the earlier introduction of
slumped and
cast
Cast may refer to:
Music
* Cast (band), an English alternative rock band
* Cast (Mexican band), a progressive Mexican rock band
* The Cast, a Scottish musical duo: Mairi Campbell and Dave Francis
* ''Cast'', a 2012 album by Trespassers William
* ...
vessels.
Cold-cut vessels
This technique is related to the origin of glass as a substitute for
gemstone
A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, ...
s. By borrowing techniques for stone and
carved gems
An engraved gem, frequently referred to as an intaglio, is a small and usually semi-precious gemstone that has been carved, in the Western tradition normally with images or inscriptions only on one face. The engraving of gemstones was a major l ...
, artisans were able to produce a variety of small containers from blocks of raw glass or thick moulded
blanks,
including
cameo glass
Cameo glass is a luxury form of glass art produced by cameo glass engraving or etching and carving through fused layers of differently colored glass to produce designs, usually with white opaque glass figures and motifs on a dark-colored backgroun ...
in two or more colours, and
cage cup
A cage cup, also ''vas diatretum'', plural ''diatreta'', or "reticulated cup" is a type of luxury late Roman glass vessel, found from roughly the 4th century, and "the pinnacle of Roman achievements in glass-making". ''Diatreta'' consist of a ...
s (still thought by most scholars to have been decorated by cutting, despite some debate).
Glass blowing: free and mould blown vessels
These techniques, which were to dominate the Roman glass working industry after the late 1st century AD, are discussed in detail on the
glass blowing
Glassblowing is a glassforming technique that involves inflating molten glass into a bubble (or parison) with the aid of a blowpipe (or blow tube). A person who blows glass is called a ''glassblower'', ''glassmith'', or ''gaffer''. A '' lampworke ...
page. Mould-blown glass appears in the second quarter of the 1st century AD.
Other production techniques
A number of other techniques were in use during the Roman period:
*
Cage cup production
*
Cameo glass production
*
Slumping
Slumping is a technique in which items are made in a kiln by means of shaping glass over molds at high temperatures.
The slumping of a pyrometric cone is often used to measure temperature in a kiln.
Technique
Slumping glass is a highly techni ...
*
Casting
Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a ''casting'', which is ejected ...
Decorative techniques
''Cast glass'' patterns
![Brit Mus 13sept10 brooches etc 046](https://upload.wikimedia.org/wikipedia/commons/d/dc/Brit_Mus_13sept10_brooches_etc_046.jpg)
The glass sheets used for slumping could be produced of plain or multicoloured glass, or even formed of 'mosaic' pieces. The production of these objects later developed into the modern
caneworking
In glassblowing, cane refers to rods of glass with color; these rods can be simple, containing a single color, or they can be complex and contain strands of one or several colors in pattern.
Caneworking refers to the process of making cane, and ...
and
millefiori
Millefiori () is a glasswork technique which produces distinctive decorative patterns on glassware. The term millefiori is a combination of the Italian words "mille" (thousand) and "fiori" (flowers). Apsley Pellatt in his book ''Curiosities of ...
techniques, but is noticeably different. Six primary patterns of 'mosaic' glass have been identified:
*Floral (millefiori) and spiral patterns: This was produced by binding rods of coloured glass together and heating and fusing them into a single piece. These were then cut in cross-section, and the resulting discs could be fused together to create complex patterns. Alternately, two strips of contrasting-coloured glass could be fused together, and then wound round a glass rod whilst still hot to produce a spiral pattern.
Cross-sections of this were also cut, and could be fused together to form a plate or fused to plain glass.
*Marbled and dappled patterns: Some of these patterns are clearly formed through the distortion of the original pattern during the
slumping
Slumping is a technique in which items are made in a kiln by means of shaping glass over molds at high temperatures.
The slumping of a pyrometric cone is often used to measure temperature in a kiln.
Technique
Slumping glass is a highly techni ...
of the glass plate during melting.
However, by using spiral and circular patterns of alternating colours producers were also able to deliberately imitate the appearance of natural stones such as
sardonyx
Onyx primarily refers to the parallel banded variety of chalcedony, a Silicate minerals, silicate mineral. Agate and onyx are both varieties of layered chalcedony that differ only in the form of the bands: agate has curved bands and onyx has pa ...
.
This occurs most often on pillar-moulded bowls, which are one of the commonest glass finds on 1st century sites.
*Lace patterns: Strips of coloured glass were twisted with a contrasting coloured thread of glass before being fused together. This was a popular method in the early period, but appears to have gone out of fashion by the mid-1st century AD.
*Striped patterns: Lengths of monochrome and lacework glass were fused together to create vivid striped designs, a technique that developed from the lace pattern technique during the last decades of the 1st century AD.
The production of multicoloured vessels declined after the mid-1st century, but remained in use for some time after.
Gold glass
Gold sandwich glass
Gold glass or gold sandwich glass is a luxury form of glass where a decorative design in gold leaf is fused between two layers of glass. First found in Hellenistic Greece, it is especially characteristic of the Roman glass of the Late Empire ...
or gold glass was a technique for fixing a layer of
gold leaf
Gold leaf is gold that has been hammered into thin sheets (usually around 0.1 µm thick) by goldbeating and is often used for gilding. Gold leaf is available in a wide variety of karats and shades. The most commonly used gold is 22-kara ...
with a design between two fused layers of glass, developed in
Hellenistic glass
Hellenistic glass was glass produced during the Hellenistic period, from the conquests of Alexander the Great (356-323 BC) to the expansion of the Roman Empire (second half of the 1st century BC - 476) in the Mediterranean, Europe, western Asia a ...
and revived in the 3rd century. 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
The Catacombs of Rome ( it, Catacombe di Roma) are ancient catacombs, underground burial places in and around Rome, of which there are at least forty, some rediscovered only in recent decades. Though most famous for Christian burials, either i ...
by pressing them into the mortar. The great majority are 4th century, extending into the 5th century. Most are Christian, but many pagan and a few Jewish; their
iconography
Iconography, as a branch of art history, studies the identification, description and interpretation of the content of images: the subjects depicted, the particular compositions and details used to do so, and other elements that are distinct fro ...
has been much studied, although artistically they are relatively unsophisticated. In contrast, a much smaller group of 3rd century portrait levels are superbly executed, with pigment painted on top of the gold. The same technique began to be used for gold
tesserae
A tessera (plural: tesserae, diminutive ''tessella'') is an individual tile, usually formed in the shape of a square, used in creating a mosaic. It is also known as an abaciscus or abaculus.
Historical tesserae
The oldest known tesserae ...
for mosaics in the mid-1st century in Rome, and by the 5th century these had become the standard background for religious mosaics.
[Beckwith, John, ''Early Christian and Byzantine Art'', pp. 25–26, Penguin History of Art (now Yale), 2nd edn. 1979, ]
Other decorative techniques
A number of other techniques were in use during the Roman period, including
enamelled glass
Enamelled glass or painted glass is glass which has been decorated with vitreous enamel (powdered glass, usually mixed with a binder) and then fired to fuse the glasses. It can produce brilliant and long-lasting colours, and be translucent or o ...
and
engraved glass
Engraved glass is a type of decorated glass that involves shallowly engraving the surface of a glass object, either by holding it against a rotating wheel, or manipulating a "diamond point" in the style of an engraving burin. It is a subgroup of ...
.
Tesserae and window glass
Shards of broken glass or glass rods were being used in mosaics from the Augustan period onwards, but by the beginning of the 1st century small glass tiles, known as
tesserae
A tessera (plural: tesserae, diminutive ''tessella'') is an individual tile, usually formed in the shape of a square, used in creating a mosaic. It is also known as an abaciscus or abaculus.
Historical tesserae
The oldest known tesserae ...
, were being produced specifically for use in mosaics.
These were usually in shades of yellow, blue or green, and were predominantly used in mosaics laid under fountains or as highlights.
Around the same time the first window panes are thought to have been produced.
The earliest panes were
rough cast into a wooden frame on top of a layer of sand or stone,
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.
[Forbes, R. J., 1966. ''Studies in ancient technology V''. Editors: Leiden, Brill.]
Chemistry and colours
See also
modern glass colors.
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.
See also
*
Ancient glass trade
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 va ...
*
Speyer wine bottle
The Speyer wine bottle (or ''Römerwein'') is a sealed vessel, presumed to contain liquid wine, and so named because it was unearthed from a Roman tomb found near Speyer, Germany. It is considered the world's oldest known bottle of wine.
Histor ...
References
Bibliography
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*Amrein, H.,2001, L'atelier de verriers d'Avenches. L'artisanat du verre au milieu du 1er siècle après J.-C., Cahiers d'archéologie romande 87, Lausanne 2001.
*Baxter, M. J., H. E. M. Cool, et al., 2006. Comparing glass compositional analyses. ''Archaeometry'' 48/3, 399–414.
*Biek, L. and J. Bayley, 1979. Glass and other Vitreous Materials. ''World Archaeology'' 11, Early Chemical Technology/1, 1–25.
*Brill, R. H., 1999. ''Chemical Analyses of Early Glasses''. New York, Corning Museum of Glass.
*Caldera de Castro, M. d. P., 1990. Roman glass in southwest Spain. In ''Annales du 11e Congres''. Amsterdam.
*Caron, B., 1993. A Roman Figure-Engraved Glass Bowl. ''Metropolitan Museum Journal'' 28, 47–55.
*Degryse, P., 2014. Glass Making in the Greco-Roman World, Results of the ARCHGLASS Project, Leuven University Press.
*Dussart, O., B. Velde, et al., 2004. Glass from Qal'at Sem'an (Northern Syria): The reworking of glass during the transition from Roman to Islamic compositions. ''Journal of Glass Studies'' 46, 67–83.
*Evison, V. I., 1990. Red marbled glass, Roman to Carolingian. In ''Annales du 11e Congres''. Amsterdam.
*Facchini, G. M., 1990. Roman glass in an excavational context: Angere (VA). In ''Annales du 11e Congres''. Amsterdam.
*Fleming, S. J., 1999. ''Roman Glass; reflections on cultural change''. Philadelphia, University of Pennsylvania Museum of Archaeology and Anthropology.
*Forbes, R. J., 1966. ''Studies in ancient technology V''. Leiden, Brill.
*Freestone, I. C., 2005. The provenance of ancient glass through compositional analysis. ''Materials Issues in Art and Archaeology 7''.
*Freestone, I. C., 2006. Glass production in Late Antiquity and the Early Islamic period: a geochemical perspective. ''Geomaterials in Cultural Heritage: Geological Society of London''. Special publication 257: 201–216.
*Freestone, I. C., M. Ponting, Hughes, M.J., 2002. Origins of Byzantine glass from Maroni Petrera, Cyprus. ''Archaeometry'' 44, 257–272.
*Grose, D. F., 1991. Early Imperial Roman cast glass: The translucent coloured and colourless fine wares. ''Roman Glass: two centuries of art and invention''. M. Newby and K. Painter. London: Society of Antiquaries of London.
*Gudenrath, W., 2006. Enameled Glass Vessels, 1425 BC – 1800: The decorating Process. ''Journal of Glass Studies'' 48, 23.
*Jackson, C. M., H. E. M. Cool, Wager, E.C.W., 1998. The manufacture of glass in Roman York. ''Journal of Glass Studies'' 40, 55–61.
*Meredith, H. G., 2015. Word becomes Image: Open-Work Vessels as a Reflection of Late Antique Transformation. Archaeopress Archaeology Series. Oxford: Archaeopres.
*Price, J., 1990. A survey of the Hellenistic and early Roman vessel glass found on the Unexplored Mansion Site at Knossos in Crete. ''Annales du 11e Congres''. Amsterdam.
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*Silvestri, A., G. Molin, et al., 2005. Roman and medieval glass from the Italian area: Bulk characterization and relationships with production technologies. ''Archaeometry'' 47/4, 797–816.
*Stern, E. M., ''Roman Mould-blown Glass''. Rome, Italy: L'Erma di Bretschneider in association with the Toledo Museum of Art.
*Stern, E. M., 1991. Early Exports Beyond the Empire. ''Roman Glass: two centuries of art and invention''. M. Newby and K. Painter. London: Society of Antiquaries of London.
*Stern, E. M., 1999. Roman Glassblowing in a Cultural Context. ''American Journal of Archaeology'' 103/3, 441–484.
*Stern, W. B., 1990. The composition of Roman glass. In: ''Annales du 11e Congres''. Amsterdam.
*Velde, B., Year. Observations on the chemical compositions of several types of Gallo-Roman and Frankish glass production. In: ''9e Congres International d'Etude Historique du Verre'', Nancy, France: Editions du Centre de Publications de L'A.I.H.V.
*Whitehouse, D., 1990. Late Roman cameo glass. In: ''Annales du 11e Congres''. Amsterdam.
*Whitehouse, D., 1991. Cameo Glass. ''Roman Glass: two centuries of art and invention''. M. Newby and K. Painter. London: Society of Antiquaries of London.(UK)
*Wood, J.R. and Hsu, Y-T. (2020): Recycling Roman glass to glaze Parthian pottery. ''Iraq'' 82, p. 259–270. https://doi.org/10.1017/irq.2020.9
*Wood, J.R. (2022): Approaches to interrogate the erased histories of recycled archaeological objects. ''Archaeometry'' https://doi.org/10.1111/arcm.12756
Further reading
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{{DEFAULTSORT:Roman Glass
History of glass
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Ancient Roman technology