RESEARCH OF MEDIEVAL GLASS VESSELS AND GLASSHOUSES IN VISEGRÁD AND DIÓSJENŐ
4. Medieval glasshouses at Visegrád Bene-ground and near Diósjenő in Nógrád county
Péter Gróf and Dániel Gróh excavated a medieval glasshouse at Visegrád - Bene-ground in 1984. The glasshouse was situated on the outskirts of the city on the riverside.
The surface of the system of holes excavated was covered by a burnt layer. The excava
tors found post-holes which belonged to a wooden construction. In the centre of the find-spot was an oval-shaped stone-surface. The functions of stone clusters were determined on the basis of the glass finds (e.g. glass-drops, glass-fragments, scrap-glass, glass-melt, and melting-pots). These artefacts were related to a medieval glasshouse, although the furnaces were not reconstructed (Figs. 5-8). This glasshouse operated between the second half of the 14th century to the first half of the 15th century. A medieval document con
cerning this glasshouse was also found. In 1491, the archbishop of Esztergom bought 5000 panes of glass from a glazier named John of Visegrád (VOIT, 1958: 283-315). An oven and a bone-carving workshop were also excavated in the proximity of this glass
house.
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Fig. 5: Plan of the oval irregular stone surface from Bene-ground at Visegrád (34, F5 Street) (E MESTER I SZABÓ, 1997.)
Fig. 6: Slag and glass melts were found in Bene-ground at Visegrád (34, Fô Street). (E MESTER I SZABÓ 1997.)
Fig. 7 Glass fragments were found in Bene-ground at Visegrád (34, Fő Street). (E. MESTER, I. SZABÓ, 1997.)
Fig. 8: Melting pot was found in Bene-ground at Visegrád (34, Fő Street).(E. MESTER, I. SZABÓ, 1997.)
Katalin H. Gyürky and Zsuzsa Miklós excavated a medieval glasshouse near Diósjenő in county Nógrád in 1987 (GYÜRKY and MIKLÓS, 1992: 69-90). A rectangular melting furnace, two round fritting and an annealing furnaces as well as a hut were discovered in the forest near Kemence brook (Fig. 9). This glasshouse was functioning during the 13th to 15th centuries.
Edit Mester and Zsuzsa Miklós excavated two additional glasshouses near the afore
mentioned fmdspot in 1995 (MESTER and SZABÓ, 1997: 8-10). A melting-furnace, an annealing-furnace and a hut were found in the second glasshouse. A melting-furnace, a fritting-furnace, an annealing-furnace and a simple furnace were excavated in the third glasshouse. These furnaces were rectangular. Many refractory pots, waste, glass glass drops, and glass fragments were found in the stoke-holes of furnaces (Fig. 10-16). These glasshouses were Working from the second half of the 15th century to the first half of the 16th century.
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Fig. 9: Plan of the excavation of the glasshouse site no.l at Diósjenö. (E. MESTER, I. SZABÓ, 1997.)
Fig. 10: Plan of the glasshouse no. 2 at Diósjenő
The chemical composition of glass samples, remains of refractory pots and raw mate
rials showed that glass-workers had been using polluted materials and lower temperatures during the melting of glass in these glasshouses than was characteristic of glass finds imported from Venice. The potassium-oxide content is typically high in the composition of glassware prepared at Visegrád and Diósjenő due to the melting technology applied, that resulted in products of lower chemical durability (Fig. 17-18)
Cheap household and industrial glass vessels were made in these glasshouses. Similar glass remains have been excavated in the neighbouring countries as well. Individual local ware and the imitations of the imported products were probably made in these glashouses.
The glass material of such products corroded considerably during centuries. The inhomo-geneity of glass materials enhanced the weathering process (Fig. 19-20).
Further examinations are necessary in order to provide more detailed answers to these questions. In the future we intend to excavate and analyse additional glasshouses in Hun
gary.
5. Summary
Generally speaking, a pronounced duality of quality and shape is visible on the glass vessels excavated in the palace and castle of Visegrád. Imported goods of high quality occurred most frequently between the second half of the 14th and the first half of the 15th century. They include Venetian small prunted goblets, bowls and biconical flasks.
Merchants ofthat period brought them to the market in complete collections as is shown by the great number of fragments found near the Roman Catholic church of Visegrád.
Imitations of the imported fine glassware used during royal celebrations soon appeared on the market. It was less elaborate and in general of lower quality.
The results of material studies and of the excavations carried out at the glasshouses suggest that the majority of vessels covered by a brown, discoloured corrosion layer had been made in Hungarian workshops. The compositions and shapes of glassware found in the glasshouses of Visegrád and Diósjenő were also observed among the vessels found in the palace and of the Lower castle in Visegrád (for example flasks with necks articulated with a simple ring, panes of glass etc.). These imitations stand out among the glass finds from the end of the 15th century, due to their unique shapes and similar compositions.
However, a diachronically improving quality can also be observed. Considering the find material that was discovered in the area of the castle, especially from the 15th and 16th
centuries (not taking into account some imported goblets), it is possible to observe that the quality of Hungarian products improved under the influence of the German and Bo
hemian glass industry (for example prunted goblets, cups, gurgling flasks, jugs etc.).
The complete inventory of glass finds from the royal palace of Visegrád shows by the great variety of vessels as well as by their stylistic richness, that the royal court enjoyed feasting in splendidly furnished buildings at lavishly set tables. We tried to distinguish between the types of Hungarian and imported glassware with the help of both scientific examinations and the excavations of glasshouses. Many local investigations are still needed in order to establish the provenances of the raw materials, the routes of trade and to identify additional glasshouses. We intend to expand this work in the near future and publish its results.
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References
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Fig. 11: Plan of the glasshouse no.3 at Diósjenő. (E. MESTER, I. SZABÓ, 1997.)
Fig. 12: The glasshouse no.2 at Diósjenő, reconstruction. (E. MESTER, I. SZABÓ, 1997.)
Fig. 13: View of furnace no.3 from the glasshouse no.2 at Diósjenő. (E. MESTER, I. SZABO, 1997.)
Fig. 14: Metal finds from the glasshouses no.2, no.3: (E. MESTER, I. SZABÓ, 1997.)1. shovel ( II/3 furnace), 2. weight (Ш/4 furnace), 3. tool (III/l furnace), 4. knife (HI/3 furnace).
Fig. 15: Melting pots from glasshouse no.3 at Diósjenő: 1. (furnace no.l), 2-4. (furnace no.3). (E. MESTER, I.
SZABÓ, 1997.)
Fig. 16/a: Stories covered glass melt, glass drops and ceramics from furnace no. 1 (glasshouse no.3 at Diósjenő) (E. MESTER, I. SZABÓ, 1997.)
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Fig. 16/b: Stones covered glass melt, glass drops and ceramics from furnace no. 1 (glasshouse no.3 at Diósjenő) (E. MESTER, I. SZABÓ, 1997.)
Glass
house at Diósjenő
Glass
house at Visegrád
Glass-house at Mátra
szentimre
Glass vessels
from Visegrád
Czech glass
houses
English glass
houses
Si02 60.81 53.5 61.94 55.03 62.31 55.7
Na20 1.67 0.28 0.25 0.24 2.94 3.1
к
2о
25.81 27.56 15.1 29.4 10.28 11.4CaO 3.88 14.45 16.56 12.35 16.3 14.8
other oxides
8.93 4.21 7.25 2.98 9.27 15
Fig. 17: Average compositions of weathered potash-glasses (weight-percent) (E. MESTER, I. SZABÓ, 1997.,K. HETTTES, 1963., R.G. NEWTON, 1975.)
Fig. 18/a: SEM micrographs of the cross section of the weathered medieval glasses from glasshouse at Visegrád (E. MESTER, í. SZABÓ, 1997.)
Fig. 18/b: SEM micrographs of the cross section of the weathered medieval glasses from glasshouse at Visegrád{E. MESTER, I. SZABÓ, 1997.)
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Fig. 19: Comparative diagram of the average compositions of Venetian type glasses (weight-percent) (Exact data are given in Fig. 4)
Fig. 20: Comparative diagram of the average compositions of weathered potash-glasses (weight-percent) (Exact data are given in Fig. 17)