Byzantine Polycandelon
by Aelfgifu
verch Morgan
Figure 1. Bronze
polycandelon with three (of nine) blown lamps.
Why a Polycandelon?
I became
fascinated with polycandelons after seeing the one at the Metropolitan Museum
of Art in
What is a Polycandelon?
Polycandelons
are an early form of candelabra utilizing oil lamps rather than candles. They
were commonly used in the Byzantine Empire from roughly the 6th to
12th century, and throughout
Makers and Owners
The components of a Polycandelon would have been made by several different people because specialized skills were utilized in the construction of each part. Skills generally needed include glass blowing and one or more forms of metalwork. I made all of the components of my polycandelon myself.
Polycandelons
were used in such places as churches and wealthy private residences. They range
from very simple, to incorporating complex designs. Religious polycandelons
often contain imagery such as crosses. Polycandelons sometimes contain purely
secular decorations like scroll patters, circles, part circles, and
quatrefoils. These designs were used to cast complex shadows. Design variations
can be seen in the pictures of polycandelons throughout this paper. As the
polycandelon I made is intended for personal use, I chose not to use Christian
symbols, and instead incorporated quatrefoils and scroll designs as decorative
motifs.[1] [2]
Overall Form
The specific forms of polycandelons vary somewhat, but basically consist of some sort of planar metal circle or rectangle containing holes which hold glass lamps. The glass lamps are either shaped like cones (fig. 1, 3, 4) or like bowls with a hollow elongated stems attached (fig. 2).
Figure 2. Plain bronze ring
polycandelon. Date Unknown.
The metals used in the polycandelons range from bronze, brass, copper alloy (fig. 1, 2, 7, 8, 10, 11, 12) or iron (chain in fig. 1 & 2) to silver (fig. 9). Polycandelons are either suspended from the ceiling with a hook or loop or from the wall by means of a bracket. I have chosen to construct my polycandelon in the form of glass cones set into a bronze ring, with a forged iron chain and loop to suspend it from the ceiling or a stand for display.
The Glass Lamps
Figure 3. Blown glass
lamps with blue spots.
Figure
4. Glass lamps, 6th – 7th century CE.
Form
I chose to make cone shaped lamps, as they appear to be more suitable to the earlier Byzantine polycandelons, instead of the stemmed lamps which seem to be more common later through out Europe. While there are some examples of lamps with decoration, undecorated lamps of a tinted color, such as seen in figure 4, are most prevalent, so I chose to emulate those.
Tools
The tools and techniques we use in glass blowing today are essentially the same type used in the Middle Ages. The basic tools of a glass blower include those used to actually melt and cool the glass and those used in forming it.
The tools used for heating and cooling are:
·
a furnace to melt and hold glass
·
a place to re-heat glass - either the mouth of
the furnace or an additional heating area modernly called a “glory hole”
·
An annealer to gradually cool off the finished
glass so it doesn’t crack while cooling.
There
are several different examples of medieval glass shops that can be observed in
pictures and from descriptions, and they all include these heating and cooling
tools. Unfortunately, while glass is available from most periods, all of the
pictures and descriptions of tools, furnaces, and techniques are from later
periods or different geographical areas. In, On Divers Arts, written by Theophilus
somewhere between the 10th and 12th centuries CE, methods
for creating a furnace for working glass and for making an annealing furnace
are described.[3] Another
example is from a description and wood cut of a furnace from the Pirotechnia of
Vannoccio Biringuccio: The Classic Sixteenth-Century Treatise on Metals and
Metallurgy (fig. 5). [4]
Figure 5. The Pirotechnia of Vannoccio Biringuccio. Furnace for melting, working, and annealing glass. Woodcut.
As other illustrations of medieval glass shops include the same aspects – an annealer, a melt furnace, and a place to re-heat glass. As all of these elements these are necessary to the craft of glass blowing, it seems reasonable to assume that they would be part of a Byzantine glass shop. These furnaces were fueled with wood, and fires were kept stoked by apprentices and workers who carefully watch the quality and heat of the fire. A modern glass shop such as the one where I made my lamps consists of the same elements, but is run off of electricity and natural (or sometimes propane) gas for fuel, with regulators to do the jobs of the apprentices and workers.
The tools used for shaping the glass are:
- a blowpipe -on which to blow the glass
- a punty -on to which the glass vessel is transferred when it is time to open the mouth of the vessel
- a marver -a place to roll the glass to shape and cool it
- jacks -used for cutting in necks and pulling necks on bottles
- tweezers -used for pulling out bits of glass
- shears -used for cutting and trimming glass
These tools can be seen in medieval illustrations in manuscripts such as seen in figure 6. Here a glass blower can be seen blowing through a pipe and marvering the bubble of glass on some sort of flat surface.
Figure 6. Depiction
of a forest glass shop from Sir John
Mandeville’s Travels, Dated 1420 –
1450. British Library,
Tools and techniques have also been mentioned in descriptions. One particularly good description is from the The Pirotechnia of Vannoccio Biringuccio (pg. 130-131):
It (glass) is worked by being blown by men’s breath with certain iron tubes... With one of these they take the glass from the pot by attaching it to the point and then wrapping it around... and giving it the form of a large ball. The first thing they do after withdrawing it is to press it on marble, turning it over and over so that it unites. The blowing on it through the opening of the tube they make it like a bubble and they elongate it by swinging it about their heads... and finally, in short, they give it the form of the vessel which they wish by warming and blowing, by pressing and enlarging. Then separating it from the first tube they take hold of it again at the bottom with the other (tube) and improve it, cutting its mouth with a pair of shears...”
These are the same type of tools used today in glass blowing, and are what I used in creation of my lamps.
Glass
Most
glass shops imported glass from other areas to use in furnaces. Usually glass
would be melted down into ingots near a source of materials, and then exported.
Then it would be crushed up into “cullet” to use in the glass furnace for
re-melting, occasionally raw materials would be shipped and combined in the
glass furnaces, and this is modernly called “batch”. Glass from failed attempts
which was not polluted by colored glass would usually be saved, crushed, and
re-melted in the form of “cullet”. Such glass was sometimes even exported from
places like
The glass I use is one of the types of glass made in the Middle Ages. There were three major kinds of medieval glass: pot-ash glass, soda-lime glass, and high-lead glass. All three types of glass were used through out the medieval world, depending on what materials were available. The glass used in the shop where I blow glass is soda-lime glass. The usual temperature for the working range of medieval soda-lime and pot-ash glass was around 1800 - 2000 degrees Fahrenheit. The glass I use is workable at temperatures between about 1900 and 2100 degrees Fahrenheit, and thus of a relatively similar working range. [8] [9]
While
I used a medieval type of glass in my projects, is much purer (clearer) than
most medieval glass except Venetian crystalo. Glass manufacturers were always
working toward glass that was more pure and clear, but usually glass was tinted
by minerals. Common tint colors included: blue-green, olive green, amber, brown,
and yellow. I chose to add an artificial tint to my glass using fine yellow
frit or crushed glass, in imitation of early crystallo attempts. I feel that
this gives my lamps a more medieval appearance. [10]
Figure 7. Polycandela. Metal. Byzantine, 500-600.
The Metal Holder
Technique
I cast a bronze ring for my polycandelon based on period methods as laid out in sources such as, The Pirotechnia of Vannoccio Biringuccio, Theophilus’ ,On Divers Arts, and, The Treatises of Benvenuto Cellini. While many polycandelons remain mostly intact, I have not been able to find a written Byzantine bronze casting account or any sort of pictorial images of Byzantine bronze casting. I therefore have relied heavily on the sources listed above for specific techniques as being the closest available sources. Theophilus is the closest in time period, as his work is thought to have originated from between the 10th and 12th centuries. However, Theophilus’ descriptions are of specific projects which differ in many elements from mine, and I referred to the later works of Cellini and Biringuccio often as they more generally discuss casting and offer other ideas about materials and techniques that are equally plausible.
I cast several rings over a series of two years experimenting with medieval techniques before achieving a good, easy to clean up casting that filled correctly. In my first attempts I experimented with both medieval mold materials and my own furnace. After several failures, I decided to concentrate entirely on my mold materials and casting method, while using a modern gas powered furnace. My next step will be building a medieval furnace in which to heat the metal. The only modern tools I used in creation of my bronze lamp holder were the kiln in which I burnt out the mold, the furnace, crucible, and the tools used to move the furnace from the crucible. All of my mold making and finishing work was done using period methods and tools.
The Mold
I used the lost-wax method to cast my bronze lamp holder. I first constructed a wax ring exactly like that which I wished to cast in bronze. As I was experimenting with methods and did not know how successful I would be, I then made a two piece plaster mold which allowed me to make as many waxes as needed. This method is mentioned in period, though in the late period, Pirotechnia.[11] I then experimented with a variety of different clay and fiber combinations for mold materials. I used a combination of techniques taken from Theophilus’, On Divers Arts, the Pyrotechnia of Vaccoccio Biringuccio, and ,the Treatise of Benvenuto Cellini on Goldsmithing and Sculpting. While Theophilus is the most contemporary in period to Byzantine bronze working, general casting techniques do not appear to differ greatly, and the, Pyrotechnia, and the Treatises of Cellini provide useful additions to the specific projects that Theophilus discusses. The basic process for making a mold which Theophilus describes uses clay or clay mixed with dung as the materials for making molds, and wax or tallow for the shape of the object which is melted out.[12] The later, sixteenth century, Pyrotechnia of Vannoccio Biringuccio, discusses casting more generally various other options for fiber additives to clay as well as the specific process of looking for clay that is appropriate for mold-making. While I did some experimentation with using horse dung as an additive for clay, the necessity of burning out my mold in my parents’ kitchen made me look for fiber alternatives. Additives mentioned in the Pyrotechnia include wool cloth clippings, coarse sand, iron scale, crushed brick, wool cardings, edges taken from cloth, hairs taken from tannery skins, dung of horses donkeys, mules, cows, chopped flax tinder, cane flowers, and finely cut straw.[13] I cast several molds using finely cut straw in combination with the clay as this was a readily available material that was definitely available to the Byzantines. After having a lot of problems with flashing I turned to another source of strengthening fiber. In my later and more successful attempt I combined clippings of wool thread with my clay, and this produced admirable results. Theophilus does not discuss what sorts of clay are desirable for casting bronze, so I once again turned to the later and more complete Pyrotechnia, which devotes an entire chapter to the subject. The desirable clay is described as: “neither unctuous nor lean, neither wholly tender nor rough, and with a grain that is fine, without pebbles or shells. When applied to a work they easily dry out without fractures and, when dry hold their own shape well. Above all they must resist fire well.”[14] Cellini says much the same thing, adding that the soil preferably comes from near rivers, as it then also has a little sandieness which is desirable.[15] Luckily for me, the soil around my parents’ house fits that description aptly, including being less than a mile from a river bank. I dug up my clay, from a likely spot (my parents’ back field), and found it to be of a nice consistency. My final mold material ended up being a combination of finely cut up wool thread and clay. I brushed on layers of wet clay first, to preserve the surface texture of the wax design, then pressed more a more dense clay and thread combination around the mold. I let the mold dry, then burned out the mold in a kiln. I kept the mold warm by insulating it in a basket of sand until the bronze was poured in, to facilitate the flow of metal.
Finishing the Lamp Holder
Theophilus mentions a wide range of tools in his text, including files, engravers, scrapers, punches, chisels, a sort of wire brush made from bundles of cut wire imbedded in lead, and shredded sticks which were all used in the finishing process.[16] I used a saw, chisels, punches, hammers, files, scrapers, and wire brushes to clean up my finished casting. I also resorted to using one power tool – an electric drill. I forget to leave holes for the chain to connect to the casting in my wax. Luckily, I did remember to leave wide spots in which to make the holes. All of the other tools I used are similar to those mentioned in Theophilus. While not achieving a perfect finish, I did achieve one that compliments the lamps and reflects light nicely, giving rich overall appearance.
Design
I chose a design based on the circle, a popular pattern which can be observed from the polycandelon examples below. I chose to not include crosses, as I want this to be a light source a private home, not for a church. I desired a fairly complex design, and based my design on holding six lamps, as that seems to have been a commonly used number. I included circles, quatrefoils, connecting bars, and scroll work based on the polycandelons shown in figures 7, 8, 9, & 10.
Figure 8. Polycandelon for 16 lamps. 7th century CE. University
of
Figure 9. Silver
Circular Polycandelon. Byzantine, 6th century CE.
Figure 10. Copper
alloy Polycandelon with Crosses,
Byzantine, 500–600. Diameter 10 1/2 in.
The Chain
The chain on all of the polycandelons I have observed is fairly small, and seems to not be welded in some cases while in others it is hard to tell if it is welded or not. All of the polycandelons with chains present are suspend from three places up to a central hook. Sometimes the chains are from the same or a similar material as the section of the polycandelon which holds the lamps, sometimes not, and in some cases no distinction is made in the description. Sometimes the chain contains medallions, and the medallions I have seen contain Christian imagery, indicating a polycandelon which was used in a religious setting. I chose to forge my chain and hook from iron as I have access to a forge used for ferrous metals which runs on a period fuel - charcoal. I did not forge weld the chain as the examples where I can see the chain clearly do not seem to be welded or brazed together. This also makes sense as welded chain is only necessary for holding a lot of weight, and even filled with oil the polycandelon dose not weigh a great deal. I also chose to not include medallions as part of my chain as I do not want to include Christian imagery on my polycandelon.
I used mild steel as the material for my chain, as real period-style iron is very expensive and mild steel is the most similar of modernly produced products.
I forged the chain in period manner, using a charcoal burning forge, a hammer, an anvil, and tongs.
Figure 11. Bronze polycandelon. Byzantine. Photograph from excavation of Hippos (Sussita).
Figure 12. Bronze Polycandelon. Byzantine, 7th to 12th century CE. Harlan J. Berk Ltd.
The Fuel and Wick
I chose to use
olive oil as the fuel for my lamp, as it would have been available in the
Wick
material for lamps also probably varied, depending on region. Possible
materials include: flax, hemp, wool, and cotton. Some Islamic lamps had narrow
glass tubes used to keep the wick in place. There is no evidence for that in
Byzantine or later period lamps. Later lamps with a narrow stem, such as seem
in
Some
method is needed to hold the end of the wick above the level of the oil in the
lamp. It is also desirable that the wick not simply be draped over the edge of
the lamp as was sometimes done with the bowl shaped pottery and metal lamps,
because the steep sides will not keep the wick above the fuel. The modern
method for holding up the floating wick in glass Christian and Jewish
liturgical lamps is to use a cork float with a thin metal sheet on top of it. A
wax-dipped wick is inserted through this with the flame end just above the
metal. Sometimes metal holders are also placed on the top of lamps. Metal clips
have been found on lamps in tombs in
Works Cited
<http://www.museum.upenn.edu/new/research/Roman%20Glass/index.html>.
“Glass Making in Roman Times: Lighting in the Byzantine Era.” Museum Applied
<http://www.metmuseum.org/toah/hd/litu/hod_PG.7.2000.htm>. Metropolitan
Ashbee, C.R. (translated by). The Treatises of Benvenuto Cellini on
Goldsmithing and Sculpture. Dover Publications Inc.,
Jacoby, David. “Raw Materials for
the Glass Industries of
Smith, Cyril Stanley, Martha Teach
Gnudi (translated by). The Pirotechnia of Vannoccio Biringuccio: The Classic
Sixteenth-Century Treatise on Metals and Metallurgy. Dover Publications,
Inc.
Theophilus On Divers Arts.
Translated by John G. Hawthorne, Cyril Stanley Smith. Dover Publications, Inc.,
Toso, Gianfranco. Murano: a History of Glass. Arsenale Editrice. 2000.
Tyson, Rachel. Medieval Glass
Vessels Found in