Thursday, March 30, 2023

Documentation: Reproduction of 14th century Islamic Glass Weights

Baroness Ginevra Lucia Di Namoraza
Figure 1


What? A selection of Islamic Glass Weights. The weights are small, round glass discs often with an impressed inscription of the name and title of the caliph or the name of the governor on them.[1]

Where? Egypt, Islamic countries
When? Popular through cultures and history but will be focussing on the 14th Century extant pieces from Egypt.
Figure 2


Why ? They are a unique piece with a very interesting history and function. They could be used in several useful ways within an SCA context including the use of them as personal tokens, as a fancy stamp
on scrolls or as game pieces. “Small glass discs with Arabic inscriptions present an important record of the early Islamic economic system as well as the organisation of the glass industry”[2]
Figure 3

Glass weights came in many sizes and denominations. They were regulated and used in medieval Egypt to measure many different items, from grains and olive oil to coins. Metal coins varied in weight and did not always contain
pure gold and silver. For these reasons, in market transactions the weight of precious metal coins would be measured on a balance against glass coins in order to determine a correct sum of money. Glass weights were thus not used as currency but as a means to weigh metal coins accurately. Moreover, their common use in commercial affairs is recorded in medieval letters written by merchants who used the Arabic verb "to weigh" (wazana) as a synonym for "to pay."
Figure 4
[3]

Details of the extant pieces: There are many centuries of wear on the glass that is on display. This means that colours and details are faded, and many of the weights have faults such as chips etc. The extant weights demonstrate the variety in size, shape, and inscriptions.


Details of the Recreation: 
Figure 5


Glass weights were made by impressing an inscribed stamp into a measured globule of glass while it was still in a semi-liquid state.[4] 

I chose to recreate a few the glass tokens that are on display in a variety of museums to ensure historical accuracy. 

I worked with each museum's high-resolution images to recreate the piece with their unique characteristics. 
Figure 6

I have then taken creative liberty with the stamps and made several of the glass weights ‘in the style of’. 

Some of these stamps I created by carving soapstone (the Lochac crest, the Islamic script) and engraving brass (the raven). 

These coins require precise movement of the glass, and patience and time melting it slowly and accurately so that the colour is not damaged and that the glass is melted carefully so that it isn’t stressed (it can fracture if so). 
Figure 7

Each coin takes 20 to 30 minutes to make, and if the press of the stamp isn’t clean enough, it must be remelted within a certain amount of time and redone, or the glass is more likely to crack or shatter. 

I have been working on developing my skill at melting glass and shaping it over the last year. I have learnt a lot, including where in the flame certain

glass must be placed so that it doesn’t ruin the colour or texture. 
Figure 8

I have learnt how to steadily place my hands and the glass to keep it at the right temperature. 

The coin weights presented a variety of challenges. Glass is a dangerous, sometimes fickle substance, and certain colours only work properly at a certain heat. 

Some of the trickier techniques that I used for this project include:


Pressing
Figure 9
the molten glass with a stamp with enough pressure to leave a mark. If this isn’t done at the precise correct timing though, the glass can become subtly too hard and slippery and the press can slip, risking burn injuries. (Ask me how I know!)
Studying each (photo of) bead in a variety of lights to get an accurate grasp of the details and finishes required.
Working with tricky colours such as white, light brown, and light blue which can be easy to “burn” or mutate colour.

Using techniques such as flattening the weights in a circular shape and then pressing carefully.

Figure 10
Details of the equipment and resources

I used a graphite paddle, a knife, fire annealing and gravity. I try to use the least tools possible and authentic equipment that would have been used by the glassmakers of the time. 

Apart from my fire set-up, all the equipment I have used would have been used at the time as well.

Figure 11
Glass artisans would have created a small kiln or furnace. The broken recycled glass would be put into the furnace through holes in the side to melt in a dish inside the furnace. Air was pumped into the furnace to keep the charcoal hot.[6]

I use a hot head torch and MAPP gas. In the future I have plans to recreate a small portable kiln but melting glass in a small kiln is very difficult as getting the heat hot enough to melt the glass is a struggle.


Figure 12
Glass would then be moved to an annealing dish in the furnace. This would prevent thermal shock, lowering the chances of the bead cracking.

Instead of annealing them in a furnace, I use a product called vermiculite to allow the glass to cool down slowly. I also use a kiln. In the future, I would like to try annealing them in a furnace to see what it is like.
Future Projects:


Figure 13
In the future, I would like to continue finding obscure glass items as they are quite interesting.

I would like to practice more difficult skills, e.g., larger sizes.  

For this project, I would match the weight more accurately, and the press form.

I am enjoying creating pieces from different times and cultures and I will

continue to develop my skills by choosing challenging projects.

I also enjoyed working with museums in previous projects, and I would like to continue working with

people like this. Not only was it very educational and rewarding, but it resulted in me contributing to

the historical accuracy of the museum- which I thought was cool!

I also intend to work on another historical recreation of a glass making set up.

Primary Resources: 

High-Resolution Copy of the extant beads. Can be found in Image credits.


Secondary Resources: 


  • Al-Gailani, Noorah. "Glass weight" in Discover Islamic Art, Museum With No Frontiers, 2023.
  • Bates, M.L. The function of fāṭimid and ayyūbid glass wėights. J. Econ. Soc. Hist. Orient/Journal de l'histoire economique et sociale de l'Orient 24, 63–92. 1981.
  • Guido, Margaret. The Glass Beads of Anglo-Saxon England: c. AD 400-700, Boydell Press, 1999.
  • Holgate, Barbara. “The Pagan Lady of Peel”, St. Patrick’s Isle Archaeological Trust, 1987.
  • Morton, A.C. Heavy Minerals in Provenance Studies. In: Zuffa, G.G., Ed., Provenance of Arenites, Reidel, Dordrecht, 249-277. 1985.
  • Regia Anglorum: https://regia.org/
  • Schibille, Gratuze, Ollivier, Blondeau. Chronology of early Islamic glass compositions from Egypt. Journal of Archaeological Science, 104, pp.10-18. 2019

 

Image credits

Websites     


[1] Bates 1993

[2] Al-Gailani 2023

[3] Al-Gailani 2023

[4] Morton 1985

[5] Regia Anglorum

[6] Guido


Further Research/ Evidence:

  • https://art.thewalters.org/detail/25429/menorah-token-2/
  • https://art.thewalters.org/detail/11026/inscribed-pound-weight/
  • https://art.thewalters.org/detail/14979/deesis-2/

By at

No comments:

Post a Comment

Subscribe to: Post Comments (Atom)