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A cage cup,(), also ''vas diatretum'', plural ''diatreta'', or "reticulated cup" is a type of luxury Late Roman glass vessel, found from roughly the 4th century, and "the pinnacle of Roman achievements in glass-making".〔New Scientist〕 ''Diatreta'' consist of an inner beaker and an outer cage or shell of decoration that stands out from the body of the cup, to which it is attached by short stems or shanks. About fifty cups or, more often, fragments have survived,〔Bonhams〕 and there are only a few in near-complete condition. Most have a cage with circular geometrical patterns, often with an "inscription", or phrase in letters above the reticulated area as well. Some have a flange, or zone of projecting open-cut moulding, above the lower patterns and below the lettering (only illustrated here by the Cologne cup in the gallery). Even rarer are examples with scenes with figures, of which the Lycurgus Cup in the British Museum is the only complete example to survive, though there are other fragments. In this the rest of the "cage" is made up of a vine that entraps Lycurgus. None have a foot. All were clearly difficult to make, and no doubt very expensive, like the other spectacular type of luxury Roman glass,〔Bonhams〕 cameo glass objects like the Portland Vase. Both the technology used to make them and the way they were used are still the subject of some debate among specialists. ==Technology== Cage cups, ''diatreta'', are mentioned in Roman literature,〔Martin, Susan Dunbar - Imperitia: ''The Responsibility of Skilled Workers in Classical Roman Law'' American Journal of Philology – Volume 122, Spring 2001, pp. 107–129, in respect of a ''calicem diatretum'' – related law, mentioned by Ulpian〕 and the dates assigned to examples (not necessarily by the same people) range from around the mid-third to the mid-4th century,〔Specifically it has been suggested that the Lycurgus Cup refers to a political event in 324.〕 at the same time as the late Roman cameo glass vessels. They appear to have been made of similar glasses, and there is also evidence that some late vessels may have been combinations of cameo and cage-cup techniques.〔Whitehouse, D., Late Roman cameo glass, in Annales du 11e Congres. 1990: Amsterdam.〕 The main division is between cups with figures, whether or not accompanied by reticulated patterns, and those without. Some have inscriptions and flanges with ovolo decoration; others do not. Most have a narrow beaker shape, but others a wider bowl-like one.〔Bonhams〕 Since the first publication on the subject in 1680 it has mostly been accepted that the cage cups were made by cutting and grinding a blank vessel of solid thick glass, a laborious technique at which the Greeks and Romans were very experienced from their passion for hardstone carvings and engraved gems in semi-precious stones. An alternative theory, once rejected but recently revived, suggests that this is only true of the rim of the vessels and the cutting of the fixed cage, but not for the joining of beaker and its cage; these would have been made separately and fused when hot.〔The main current proponent is the German glass historian Rosemarie Liercke - see external links for her website, which has English accounts of her theories, controversial on this and other matters.〕 For example, it is claimed that the smooth joins on the Munich cup show the fusion of the cage to the main cup, though the cage itself is carved. However this remains controversial, and a fragmentary cup found in Corinth in the 1960s is said to show no evidence of joints where the cage meets the main cup when examined under a microscope.〔Whitehouse, 83-84; (Corning Cage Cup )〕 Apart from carved gems, a small fragment of an openwork pattern in reticulated silver has survived in a large hoard of Roman silver chopped up in the 5th century as bullion, and buried in Scotland at Trapain Law, now in the Royal Museum of Scotland. The fragment shows a pattern based on circles, that is very similar to the glass ''diatreta'', suggesting that the same style may have been used in silver plate, though which came first is unknown.〔Fleming, 110〕 Some examples add difficulty to the manufacturing process by using different colours on the cage, like the Milan and Cologne cups, but most are plain glass, like those at Munich and Corning. For the special technology of dichroic glass, which changes colour when light passes through it, see the article on the best example, the Lycurgus Cup. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cage cup」の詳細全文を読む スポンサード リンク
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