Panel 3.27 – Roman and Late Antique glass production

Organiser/Chair:

• Constanze Höpken (Universität zu Köln)

Speakers:

• Paola Puppo
  Tiburtini calices or gemmata potoria in thin walled ware: a luxury roman production of the first imperial age
• Frank Wiesenberg (Universität zu Köln)
  New light on old panes. Current results obtained by experimental archaeology: Making Roman window glass
• Miguel Cisneros (Universidad de Cantabria)
  Semiprecious stones and blue glass: An approach to the imitation phenomenom in Hispania during the roman period
• Ella Magdalena Hetzel (Universität zu Köln)
  Das Handwerk im römischen Köln

1. Paola Puppo

Tiburtini calices or gemmata potoria in thin walled ware: A luxury roman production of the first imperial age
Gemmata potoria is a particular production of the ager Romanus, represented by drinking vessels (beakers, mugs and small cups) decorated with vegetable motifs and embellished with gems of colored glass paste (pasta vitrea). This type of pottery, dating from the Augustan to the imperial period until the Flavian age, was found in funerary contexts (an example comes from the child’s grave of the necropolis Settecamini) and religious contexts (many specimens have been found at the Ara Maxima in the Foro Boario and in the sanctuary of Tivoli, both dedicated to the worship of Hercules Victor). The precious decoration à la barbotine is made with points, stems and drops arranged to form phytomorphic elements with inserts of glass paste of blue gradation encapsulated in clay. These drinking vessels have a limited spread, closely linked to Rome: the specimens come from Tivoli, Rome, Palestrina, Privernum, Ostia. The examples founded in the urban contexts provide significant elements to identify the sources and the cultural traditions that this ware reflects. It hasn’t been produced only for the libations in the funeraries and sacred contexts, but it may have been used on request by rich customers as it proved by Seneca (Epistulae to Lucilius). The production seems to lie in Tivoli, whose figulinae workshops were already fully actives in the production of fine tableware such as the so-called Italo-megarian bowls) and the thin walled ware.

2. Frank Wiesenberg (Universität zu Köln)

New light on old panes. Current results obtained by experimental archaeology: Making Roman window glass
Beginning in the first century AD, window glass was commonly used in Roman building architecture. They served as passive illumination in bath houses as well as public and private buildings, spreading from central Rome all over the Roman Empire.
Two different types of early Roman window glass can be specified. Flat, square or rectangular glass panes on the one hand, round and domed window glass (so-called oculi) on the other. Both are thick-walled, and feature a matt and a glossy side, which easily distinguishes them from the later blown Roman window glass (so-called cylinder-glass).
These two early Roman window glass types were reconstructed during the ‚Borg Furnace Project 2015’ in the Archaeological Park Roman Villa Borg’s hot glass workshop. Using a flat ceramic support, by stretching and pulling a gather of hot glass to create a square shape, Mark Taylor and François Arnaud re-created several of the matt-glossy window panes typical of the first century AD. The observable characteristics and tool marks matched those of the Archaeological Park Roman Villa Borg’s Roman fragments.
Furthermore, Mark Taylor reconstructed one of the Villa Borg’s domed window glasses by slumping a stretched hot glass disc over a hemispherical mould. Again the characteristics and tool marks were identical to those seen on the Roman fragments.
According to current research and knowledge, the slumping method seems to be the correct technique for making domed Roman window glasses, and the stretching and pulling method is likely to be the method of manufacturing the early Roman matt-glossy square or rectangular window panes. For theoretical and practical considerations, the often-suggested method of pouring hot glass into a wooden mould is very unlikely. Therefore the term ‚cast window glass’, though still widely used, is not appropriate for these glass objects.

3. Miguel Cisneros (Universidad de Cantabria) / Nova Barrero (Museo Nacional de Arte Romano de Mérida) / Alfredo Encuentra (Universidad de Zaragoza) / Esperanza Ortiz (Museo de Zaragoza) and Juan Paz (Museo de Zaragoza) / Pilar Caldera de Castro (Museo Nacional de Arte Romano de Mérida)

Semiprecious stones and blue glass: An approach to the imitation phenomenom in Hispania during the roman period
The oldest recorded glass, dating from circa 23rd century B.C., is blue and consists of a preformed cast bar originating in Eshnunna (Mesopotamia). The earliest creations made of this material were beads that imitated semiprecious stones such as lapis lazuli or turquoise.
This paper documents blue glass skeuomorphs and verifies equivalent stones revealing concurrences from a morphological viewpoint and in terms of shapes, uses or contexts, including better known glass creations imitating lapis lazuli, turquoise and sapphire, as well as blue/white designs replicating cameos.
Glass craft experimentation reveals particular artistic licences so relationships may be established with other stones not blue in colour whose decoration patterns are well defined and whose manufacture in glass could fall within the group of inspirations, interpretations or versions.
Original and imitation objects were mainly used as containers, personal adornment, ornamental inlays, games and opera sectilia.
This paper presents instances from Emerita Augusta, Colonia Celsa and Caesar Augusta. Conclusions contribute to qualifying data provided by classical authors and to presenting data on social and economic aspects regarding the users of this type of product, for imitations though they may be they may not be assumed to have been accessible to all.
This investigation work is part of the project Ficta Vitro Lapis: Glass imitations of stones in Roman Hispania (HAR2015-64142-P) (MINECO/FEDER, UE).

4. Ella Magdalena Hetzel (Universität zu Köln)

Das Handwerk im römischen Köln
For more than a hundred years, a vast amount of evidence regarding the flourishing craftwork production of the Roman period has been secured and documented within the urban center of Cologne. This abundance of archaeological source material determines how the economic situation looked like. In that purpose archeological evidence concerning profit optimization, investments, organization and requirement structure will be discussed.
In the archeological magazines of Cologne a wealth of sources for economic evidences is stored. These findings indicate pottery production, glass manufacturing, metal and wood working as well as the processing of animal and agricultural products. Overall 44 pottery workshops and 10 secondary glass huts have been documented. Furthermore there are scattered features, which correlate to non-ferrous metal industry, processing of marble inlays, production of glue and manufacturing of animal bones as well as bakery production.
In the analysis various economic topics will be treated, which all require different approaches. The research project will deepen the scientific debate connected to the economic structures of the Imperium Romanum. By means of the doctoral thesis modernist opinions will be strengthened and further developed. Through elaboration of single economic curves as well as a view on framework conditions, precise and meaningful results on the economic development will be supported.