Molding and Casting the Parthenon
"After it [gypsos "plaster," Latin gypsum] has been pulverized and water has been poured on it, it is stirred with wooden sticks....And it is wetted immediately before it is used; for if this is done a short time before, it quickly hardens and it is impossible to divide it....And painters employ it for some parts of their art....It seems to be far superior to other earths for taking impressions, and is generally used for this purpose, especially in Greece, owing to its stickiness and smoothness."
Theophrastus, On Stones (§§66–67)
Gypsum is a very soft mineral formed by the evaporation of ancient inland seas. As water in these shallow basins evaporated, its minerals concentrated and crystallized. Sulfur was exposed to oxygen to form a sulfate, which then bonded with calcium and replenished water to create sedimentary beds of gypsum (calcium sulfate dihydrate CaSO4+2H2O). When heated in a kiln, most of this water is driven off as steam to form calcined gypsum or plaster (calcium sulfate hemihydrate, CaSO4+1/2H2O). (The two molecules of CaSO4 in the equation now share only one molecule of water, which is the equivalent of half a molecule of water.) When ground into a fine white powder and water reintroduced, the hydrated gypsum again hardens and sets as plaster—or plaster of Paris, so named from the deposits of gypsum that were quarried in the eighteenth and nineteenth centuries at Montmartre on the northern outskirts of Paris.
Gypsum plaster was used by the ancient Egyptians both to provide a ground (like gesso, which is plaster mixed with a binder such as animal glue) for painting fine detail, as in the famous bust of Nefertiti, which was covered with a thin layer of plaster, or for busts of the queen herself. A millennium later, toward the end of the fourth-century BC, the Greek philosopher Theophrastus (who succeeded Aristotle to head the Lyceum) wrote De Lapidibus, the first systematic study of mineral substances, which he divides into two classes: stones (mainly precious and semi-precious) and mineral earths. Of the earths, there are types "that are unusual because of their color, smoothness, density, or any other quality" (§1), three or four of which "are useful as well as unusual" (§62). One is Samian, a red clay used for pottery; the fourth is Tymphaic earth from Tymphaea in northwestern Greece—or gypsum, as it was called by the inhabitants of nearby Thessaly.
Gypsos could mean either the mineral itself or the plaster obtained by heating it—a distinction that was not always clear; indeed, not even to Theophrastus himself. When he remarks, for example, that there were large deposits of gypsum in Cyprus that were easily extracted from the soil, he is referring to the mineral. But, in the next sentence, when he says that gypsum in Phoenicia and Syria "is made by burning stones" (§64) or "fired in a furnace" (§69), he means its calcination—the production of plaster. Whether used as mortar or for making impressions, Theophrastus was struck by gypsum's particular properties, "for it is more like stone than earth....Its stickiness [its viscidity or cohesiveness] and heat [which is exaggerated], when it is wet, are remarkable" (§65). A hydrated salt that is dehydrated during calcination and then rehydrated to form plaster: it is no wonder that Theophrastus marveled at the properties of gypsum—which seemingly metamorphosed from one element to another and then back again.
Pliny paraphrases these passages in his own discussion of gypsum, adding that the best plaster was made from the specular stone (lapis specularis or "stone mirror"), thin transparent sheets of gypsum that were used in place of glass for windows (Natural History, XXXVI.lix.182; xlv.160)—and that a close friend of Augustus once died from having ingested it to treat abdominal pain (Dioscorides, De Materia Medica, "it chokes by constriction," V.134). Pliny also records that "the first person to have modeled a likeness in plaster [gypso] of a human being" was Lysistratus (the brother of Lysippus, who sculpted the Apoxyomenos in the fourth century BC). Lysistratus also "invented taking casts from statues, and this method advanced to such an extent that no figures or statues were made without a clay model" (XXXV.xliv.153).
Readily available, easy to manipulate, and quick to harden (but also brittle, highly porous, and readily soiled), gypsum plaster was an ideal medium for casting a three-dimensional work of art. When, for example, the envoys of Ptolemy I visited Sinope on the Black Sea in the third century BC, they took a statue of Pluto but were instructed that they "should merely take an impression of that of Persephone and leave it [the original] behind" (Plutarch, Moralia: Whether Land or Sea Animals are Cleverer, XXXVI).
In the second century AD, Lucian speaks of a bronze statue of Hermes, finely tooled and contoured, standing in the market place "covered with pitch from being cast every day by the sculptors," the Hermagoras (Hermes of the Agora) complaining: "It fell just now that they who work in bronze had smeared me o'er with pitch on breast and back; a funny corslet round my body hung, conformed by imitative cleverness to take the full impression of the bronze" (Zeus Tragoedus, XXXIII). And, to be sure, a mold that could be readily transported and duplicated was far easier to use than having to measure the statue itself.
In 1954, more than four hundred plaster casts (of thirty or so different statues) were discovered in Baiae on the Bay of Naples that once seem to have been part of a Roman sculptor's workshop collection. What is significant is that they are casts of famous Greek bronzes, which must have been molded from the originals and shipped to the atelier. By comparing these casts to later Roman copies (for example, the Wounded Amazons in the Ny Carlsberg Glyptotek and Vatican Museums), Landwehr has identified at least a dozen classical statues.
Rather than serve as models for duplication in marble or bronze, plaster casts could substitute for them. Writing about AD 100, Juvenal satirizes ignorant moralists who fill their houses with plaster (gypso) busts of the great philosophers so as to appear wise themselves (Satires, II.4). Nor were casts necessarily inferior to their more expensive counterparts and could be legitimate works of art in themselves. Pausanias remarks once having seen in a house an image of Dionysus "made of gypsum and adorned with painting" (Description of Greece, IX.32.1). And Arcesilaus, who sculpted the statue of Venus Genetrix in the Forum of Julius Caesar, was said by the Roman scholar Varro to have models in clay that sold for more than the finished works of other artists. Once, when asked to make a wine bowl, he "made a model in plaster for the price of a talent." (A Roman talent weighed one hundred libra, a weight in silver that equates to about 24,000 sesterces.) For a model of a statue of Happiness, he was paid 60,000 sesterces by the fabulously wealthy Lucullus (Pliny, XXXV.xlv.156).
When Lord Elgin arrived at the Ottoman court in Constantinople in 1799, his mandate as ambassador was to promote British interests in the region. His own intention, as recorded by the Select Committee to the House of Commons in 1816, was "to make that appointment beneficial to the progress of the Fine Arts in Great Britain, by procuring accurate drawings and casts of the valuable remains of Sculpture and Architecture scattered throughout Greece, and particularly concentrated at Athens" (p. 2). Intriguingly, the Committee felt compelled to comment at the time that "this recommendation was in no degree encouraged, either at the time or afterwards" (p. 5). Indeed, Elgin "looked upon himself in this respect as acting in a character entirely distinct from his official situation" (p. 6).
The second volume of Stewart and Revett's The Antiquities of Athens, which had been published in 1789, was devoted to the Parthenon and other ruins on the Acropolis,. But, even though it provided exact measurements and engravings, Elgin justified his own actions by stating that there still was nothing "to convey to Artists, particularly to Students, that which the actual representation by cast would more effectually give them" (p. 32). Elgin's agent William Hamilton expressed the same thought, "although we might possess exact measurements of the buildings at Athens, yet a young artist could never form to himself an adequate conception of their minute details, combinations, and general effect, without having before him some such sensible representation of them as might be conveyed by casts" (p. 2). What, in fact, was needed, were actual plaster casts of objects in the round.
To that end, Elgin assembled two architectural draftsmen to take measurements, two formatori to make plaster molds, and a figure painter. By May 1800, these artists had arrived in Constantinople and by August were in Athens to begin their work. But access to the Acropolis was denied for another six months and then only to draw—for a daily fee equivalent to five guineas. This was an exorbitant, even extortionate sum, that equates to perhaps £225 (or more than twice that, depending upon how inflation is calculated) and would, in other circumstances, have hired forty men and two work animals for the day.
In July 1801, however, a firman from the Ottoman Court arrived, ostensibly giving complete access to the Acropolis and its ruined temples. No longer obliged to pay a fee, Elgin's agents now could freely erect scaffolding to draw, measure, and take molds "with chalk or plaster"—and to remove obstructions, dig, and take away whatever fragments of sculpture or architecture that might be excavated. (Nothing in the letter explicitly granted permission to remove elements from the Parthenon itself, however.) Whatever interpretation Elgin had of the firman, work continued at a frenetic pace. By late 1802, just as the architects and modelers were finishing their work, Giovanni Battista Lusieri, an artist himself who supervised the men, could write to Elgin in Constantinople that all of the Parthenon's west frieze had been molded, as well as the best preserved parts of the north frieze (subsequently lost), and four of the best metopes on the south size. Elgin departed Constantinople in January 1803, his appointment at an end. In the eighteen months since obtaining the firman, he had—for good or ill—accomplished all that he had intended.
The triumph was short lived, however. On his way home, Elgin was arrested in Paris as a foreign national and detained in France. When he finally returned to England three years later, Richard Payne Knight, a classical scholar and arbiter of taste in England, promptly declared to Elgin that the Parthenon marbles were, in fact, Roman creations from the time of Hadrian. He lost his seat as a Scottish peer in the House of Lords—and his wife. Exhausted by childbirth (or to force a separation), she refused any further intimacy with him. Elgin then discovered that she was having an affair with a family friend. In 1808, there was a scandalous divorce, the adultery made all the more public by Elgin insisting on trials both in Scotland and England. Four years later, Lord Byron savagely lampooned Elgin in The Curse of Minerva and Childe Harold's Pilgrimage, holding him responsible for looting "The last poor plunder from a bleeding land" (Canto II.xiii).
In debt and the expectation of his wife's fortune lost to him, Elgin was forced to sell the Parthenon marbles to the British Museum in 1816 for half what he had spent in acquiring them.
In molding the figures of the Parthenon, Fauvel (who had made the earliest casts in 1786) and Elgin's formatori used the same technique: plaster piece-molding, in which sections of a statue are molded individually and the pieces (tasselli) assembled to create a complete mold of the original, when was cast. It is an exacting and time-consuming process that requires the skills of a specialist. When Elgin hired his own formatori, only six were to be found in all of Rome; the rest were working in France, presumably on the increasing collection of looted art in the Louvre.
Much as one would assemble a puzzle over a three-dimensional surface, the modeler must imagine the sculpture divided into sections—of which there might be scores or even hundreds, each mapped in the mind. They then are molded, the edges greased so as not to stick, and carefully keyed or fitted together. Undercuts, protruding or indented sections of a statue that would make it otherwise impossible to remove a cast from the mold without breaking it, require even more and smaller molds.
Plaster warms very slightly as it dries and expands, pressing into the sculpture to capture the most minute detail. To prevent it from adhering to the surface (Theophrastus' "stickiness"), oil or lard first has to be applied to the surface, which is molded in sections, with no one piece so large that, once the plaster has set, it too cannot be removed without breaking. Often, heads, arms, hands and feet were molded separately and later attached to the torso with dowels.
Once the entire statue has been molded, the tasselli were oiled again (this time on the exterior) and another, thicker coating of coarse plaster applied to form a mother mold (madreforma) to hold them in place. The tasselli were separated from the sculpture and fitted back into the mother mold, which usually was cast in two parts. Oil was reapplied to the inner surfaces of the tasselli and the halves of the mother mold tightly bound together. Finally, a fine slurry of plaster was poured into the mold to thoroughly coat the inside (so as to capture the detail of the sculpture) and a coarser mixture applied for strength. Once it had set but still was damp, the mold was separated to reveal the final casting. Given the intricacy of the operation, it is no wonder that Landwehr, working with a sculptor trained in traditional copying techniques, has calculated that four-hundred hours might have been required to make a cast of a full-sized statue.
This etching (Table VI) is from an illustrated manual for students of sculpture that was published in 1802, the same year that Elgin was having the Parthenon marbles molded, removed, and shipped to England. Caradori, a sculptor and restorer himself at the Accademia in Florence, explains in Article VI the various steps in plaster casting, and the tools and techniques that are needed. It is a collaborative process: working from the bottom up, the man on the right applies plaster to a statue with a metal spatula, his initial effort already tightly secured and allowed to set. Dowels to hold the molds securely in place are being carved while another man on the left coats the inside of a mold with oil and lard from the jars next to him. The greased mold then is filled with plaster (gesso) to make a cast, one of which lies drying on the table at the back. On the floor, there is a bag of dry plaster, a tub in which to store it, and a jug of water and basin for mixing.
"As you enter the temple that they name the Parthenon, all the sculptures you see on what is called the [east] pediment refer to the birth of Athena, those on the rear [west] pediment represent the contest for the land between Athena and Poseidon."
Pausanias, Description of Greece (I.24.5)
This red chalk drawing is attributed to Jacques Carrey, who sketched it in 1674. At the time, the head of the reclining goddess still was intact. In the extreme corner is the isolated head of one of the horses that drew the chariot of the goddess Selene, here sinking into the ocean as the Moon sets.
The photographs likely are of Aphrodite resting in the lap of her mother Dione, although Thalassa (Sea) in the lap of Gaia (Earth) has been suggested. (Smith regarded them as The Fates.) Carved from a single block of marble, it was removed from the east pediment of the Parthenon in 1802 and acquired by the British Museum in 1816 when Elgin was sold his collection (Smith, Catalogue, 303, figures L and M).
The plaster cast is in the Acropolis Museum. Looking carefully, a slight ridge can be seen running across the chest of the goddess. It is the result of plaster having seeped into the spaces between the tasselli. Rather than being sanded away, these fine seams often were left as a demonstration of the molder's art and a measure of how accurately individual pieces had been cast—and how newly created the mold itself was. With repeated castings, the lines between the individual tasselli in an old and worn mold became increasingly ragged and rough.
References: Casting the Parthenon Sculptures from the Eighteenth Century to the Digital Age (2021) by Emma M. Payne; "Plaster Casts in Antiquity" (2010) by Rune Frederiksen, in Plaster Casts: Making, Collecting and Displaying from Classical Antiquity to the Present, edited by Rune Frederiksen and Eckart Marchand, pp. 13-33 (also "The Baiae Casts and the Uniqueness of Roman Copies" by Christa Landwehr, pp. 35-46); "An Aristogeiton from Baiae" (1970) by Gisela M. A. Richter, American Journal of Archaeology, 74, 296-297; Lord Elgin & the Marbles (1998) by William St. Clair; A Catalogue of Sculpture in the Department of Greek and Roman Antiquities, British Museum (Vol. I) (1892) by A. H. Smith; Theophrastus: On Stones (1956) translation and commentary by Earle R. Caley and John F. C. Richards; "Some Mineralogical Problems in Theophrastus' De Lapidibus" (1967) by D. E. Eichholz, The Classical Quarterly, 17(1), 103-109 (Eichholz also has translated De Lapidibus, 1965); Lucian of Samosata: Works (Vol. III) (1905) translated by H. W. Fowler and F. G. Fowler (Loeb Classical Library); Plutarch: Moralia: On the Intelligence of Animals (Vol. XII) (1957) translated by William Helmbold (Loeb Classical Library); Report from the Select Committee of the House of Commons on the Earl of Elgin's Collection of Sculptured Marbles (1816); Memorandum on the Subject of The Earl of Elgin's Pursuits in Greece (1811); Istruzione Elementare per gli Studiosi della Scultura [Elementary Instruction for Students of Sculpture] (1802) by Francesco Carradori (translated by Matti Kalevi Auvinen, 2002); Plaster Casts and How They Are Made (1899) by Frank Forrest Frederick (Chapter XII).
See also The Wounded Amazon, Samian Ware, and Stewart and Revett.
