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Roman Dichroic Glass: Two Contemporary Descriptions?

All About Glass

Dichroic (two-colored) glass is so called because it appears to be one color in reflected light and another color when light shines through it. Only a handful of Roman dichroic glass objects are known to exist. The most famous of these is the Lycurgus Cup, which is opaque green in reflected light and translucent red in transmitted light.1 If the rarity of Roman dichroic glass today reflects its availability in Roman times, it was very rare indeed; fragments included, we know of more than 50 late Roman cage cups, but fewer than 10 dichroic objects.2

It would be surprising if objects of such rarity and with the extraordinary property of changing color failed to excite comment among the privileged Romans who saw them. The purpose of this note is to draw attention to two passages in the literature of the day that may contain such comments. They are not unknown to students of ancient glass, but neither of them, I suspect, has received the attention it deserves.

The first passage occurs in Vopiscus' life of the third-century pretender Saturninus. This contains a letter purportedly written by the emperor Hadrian (117–138) when he was in Egypt. In it, the emperor describes a gift to his brother-in-law Severianus in Rome:

Calices tibi allassontes versicolores transmisi, quos mihi sacerdos templi obtulit, tibi et sorori meae specialiter dedicatos; quos tu velim festis diebus conviviis adhibeas (SHA, Firmus, Saturninus, Proculus et Bonosus VIII.10).

The passage is unambiguous: "I have sent you parti-colored cups that change color; presented to me by the priest of a temple. They are specially dedicated to you and to my sister. I would like you to use them at banquets on feast days.”3

The letter is apocryphal, and the "cups that change color'' are much more likely to have been exotic rarities, perhaps from Egypt, in the time of Vopiscus than in that of Hadrian. We know from internal evidence that Vopiscus wrote in the early years of the fourth century A.D.; he mentions Junius Tiberianus as holding the office of praefectus urbi (which he did in 303–304), Constantius as imperator (305–306), and Diocletian as iam privatus (he retired to private life in 305). It is also evident that the biography was completed before the death of Diocletian in 316, and perhaps before the death of Galerius in 311.4 The passage suggests, therefore, that dichroic vessels (“cups that change color") were being made at the beginning of the fourth century (but see note 7).

The second passage is less straightforward and much more tantalizing. It occurs in the novel Leukippe and Cleitophon by Achilles Tatius, an Alexandrian who seems to have lived in the second century A.D.5 The hero, Cleitophon, is at Tyre, where he attends a banquet given by his father on the feast day of Dionysus. During the meal, the host offers libations from a most unusual vessel:

φτλουμούμενος ούν ό παιηρ τά τε άλλα παραοκενάσας είς τό δείπνον έτυχε πολυτελέστερα και κρατήα παρεοήκατο ίρόν τοϋ θεοϋ πολυτελή, μετά τόν Τλαύκου τοϋ Χίου δεύτερον. “γάλου μέν τό πάν έργον όρωρυγμένης’ κύκλψ δέ αύτόν άμπελοι περιέοτεφον άπ’ αύτοϋ τοϋ κρατήρος πεφυτενμέναι’ οί δέ βότρνες πάνιη περικρεμάμενοι’ όμφαξ μέν αύτών έκαοτος έφ’ όαον ήν κενός ό κρατήρ’ έάν δέ έγχέης οϊνου, κατά μικρόν ό βότρυς ύποπερκάζεται και οταφυλήν τήν όμφακα ποιεί. Διόνσος δέ έντετύπωται τών βοτρύων πλήσιον, ϊνα τήν άμπελον οϊνφ γεωργή (ΙΙ.3.1–2).

The lines may be translated as follows: "My father, wishing to celebrate it with splendor, had set out all that was necessary for the dinner in a rich and costly fashion: but especially a precious bowl to be used for libations to the god, one second only to that of Glaucus of Chios. The material of which it was made was crystal. Vines crowned its rim, seeming to grow from the cup itself; their bunches drooped in every direction. When the cup was empty, each grape seemed green and unripe, but when wine was poured into it, then little by little the clusters became red and dark, the green crop turning into the ripe fruit. Dionysus, too, was represented, near the bunches, as the husbandman of the vine and the vintner."6

Clearly, the author is describing a cup with elaborate decoration, apparently in relief, of vines with bunches of grapes and the figure of Dionysus. Regardless of the material from which it was made, the object changed color from green to red when it was filled with wine. Equally clearly, the subject matter and the color change were thought to be highly appropriate for a cup used at a feast in honor of Dionysus, who taught men the secret of winemaking.

Taken at face value, the description most readily applies to a transparent green vessel with molded or wheel-cut ornament, which becomes dark red when it is filled with red wine. This, however, is hardly remarkable — the same could be said of almost any green bottle — even if the color change was restricted to the bunches of grapes, perhaps by making the wall much thinner in these areas than elsewhere on the cup.

It is possible, therefore, that we should seek an alternative explanation. One hypothesis (doubtless, there are others) is that Achilles Tatius was describing a real object, which he knew only from hearsay, and misunderstood what he had heard. The change from green to red, perhaps, had nothing to do with the addition of red wine (logical as this may have seemed to the author), but occurred because the glass was dichroic. Such a suggestion appears to go a long way beyond the evidence until one remembers that a Roman object which is decorated with a vine bearing bunches of grapes, which has figures including the god Dionysus, and which changes from green to red because the glass is dichroic, actually exists. That object is the Lycurgus Cup. This comparison leads to the further speculation that the craftsman who cut the Lycurgus Cup exploited the color change inherent in the blank for a specific and highly appropriate purpose: to symbolize the ripening of grapes and their conversion into wine. If this is so, the Lycurgus Cup, like the cup seen by Cleitophon at Tyre, may have been used at ceremonies and feasts in honor of Dionysus.7

This article was published in the Journal of Glass Studies, Vol. 31 (1989), 119–121.

1. [Kenneth Painter], "The Lycurgus Cage-Cup," in Donald B. Harden, Hansgerd Hellenkemper, Kenneth Painter, and David Whitehouse, Glass of the Caesars, Milan, I987, pp. 245–249.

2. For other Roman dichroic fragments, see D. B. Harden and Jocelyn M. C. Toynbee, "The Rothschild Lycurgus Cup," Archaoeologia, v. 97, 1959, pp. 179–212, especially p. 188. The authors apparently were unaware that the cage cup from Soria in Spain is also dichroic (ibid., pp. 210–211, no. B11). See also Robert H. Brill, "The Chemistry of the Lycurgus Cup," Proceedings of the VIIth  lnternational Congress on Glass, Comptes Rendus II, Brussels: International Congress on Glass, I965, section B, paper no. 223, pp. 1–13, especially p. 3; Axel von Saldern, Ancient and Byzantine Glass from Sardis, Cambridge and London, 1980, p. 17, no. 63. There is an unpublished dichroic fragment in The Corning Museum of Glass (acc. no. 78.1.17).

3. I have translated calices... allassontes tersicolores as "parti-colored cups that change color" because allassontes (the present participle of the Greek verb  υλλάοοω means "changing" or even "alternating" (Henry George Liddell and Robert Scott, A Greek-English Lexicon, A New Edition Revised... by Sir Henry Stuart Jones with the assistance of Robert McKenzie, Oxford, 1940, p. 68), and versicolores means either "of various colors" or "that change color" (Charlton T. Lewis and Charles Short, Harper's Latin Dictionary. A New Latin Dictionary, New York, Cincinnati, and Chicago, 1907, p. 1975). The passage was first quoted in connection with the Lycurgus Cup by A. Nesbitt, A Descriptive Cat. of the Glass Vessels in the South Kensington Museum, London, 1878, p. 33. Mary Luella Trowbridge (Philological Studies in Ancient Glass, Urbana, 1930, pp. 165–166) translates the words as "variously shaded ... changeable, or iridescent ... goblets." Harden and Toynbec ([note 2], p. 188) note that "versicolor may merely mean polychrome (parti-coloured), but allassontes certainly suggests a change from one colour to another."

4. David Magie, The Scriptores Historiae Augustae, Cambridge, Mass., and London, 1921, v. 1, pp. xiv–xv.

5. N. G. L. Hammond and H. H. Scullard, ed., The Oxford Classical Dictionary, 2nd ed., Oxford, 1970, pp. 5–6, s.v. "Achilles Tatius."

6. The use of "crystal" to translate ύάλον...όρωρυγμένης is deliberately ambiguous; literally, the words mean "glass dug out of the ground." The author's failure to tell us whether the cup was made of glass or some natural substance is understandable. Even in the early 1950s, when the Lycurgus Cup first came under careful scrutiny, a distinguished glass technologist, Prof. W. E. S. Turner, advised caution about accepting the object as undoubtedly of glass, while a mineralogist, Dr. G. F. Claringbull, expressed the view that the material was not a mineral: Harden and Toynbee [note 2], p. 180. For the meaning of ϋαλος see Trowbridge [note 3], pp. 22–33; the passage in question is quoted on p. 26, n. 16. Dr. Robert H. Brill kindly suggested that the phrase κατά μικρόν  ("little by little") may suggest that if the vessel was green, the bunches of grapes were hollow and were connected with the interim: of the cup by small openings, in which case they might have filled slowly and so changed gradually from green to red.

The object with which the cup was compared has not survived, but it is described by Herodotus. It was a large silver krater on a welded iron stand. "This is the most notable among all the offerings at Delphi, and is the work of Glaucus of Chios, the only man of that age who had discovered how to weld iron" [I.25].

7. I am not suggesting, of course, that the object described by Achilles Tatius is the Lycurgus Cup. Quite apart from the discrepancy of dates—Leukippe and Cleitophon is attributed to the second century and the Lycurgus Cup to the fourth century—it is impossible to reconcile the author's description with the scene on the Lycurgus Cup. It is interesting to note, however, that the description (like Vopiscus' reference to calices... allassontes versicolores) may indicate the existence of dichroic glass vessels in the second century, although to the best of my knowledge, no dichroic object or fragmentary object of this date has yet been recognized.

Published on June 11, 2013