1The research and analysis of the glass material from medieval sites in Slovenia and the Balkans developed and became more numerous in the past fifty years. A short overview of the more recent studies over the last 10-15 years will be given here.

2The research of the glass from medieval sites in Slovenia leads us to believe that from the 13^th to the 15^th century glass objects came to Slovenia as imports. Products from Italian and Venetian workshops as well as typical German productions can be found in Celje, Ljubljana, Piran, Slovenj Gradec, etc. In Croatia, archive sources prove the glass masters operated in Dubrovnik as early as the 14^th century. Along the Adriatic coast, there is an abundance of shipwrecks with glass material from various workshops. In Bosnia and Herzegovina, the medieval glass material shows influences of Italian, Venetian, Bohemian and German production centres. There are also some forms that can be ascertained as local glass styles, but the production centres are questionable.

1 Slovenia – SE Alpine area (fig. 1)

3Excavations in the medieval castles and towns in Slovenia have endowed museum collections with a wealth of glassware. In this paper we would like to single out some significant finds and the most numerous glass forms that were found in archaeological contexts in Slovenia. The varied nature of the material from Slovenian sites indicates that the use of glassware was as advanced in every respect as in other parts of Europe. But there is no archaeological evidence for the existence of glass production in the medieval period. It can be assumed that glass production may have existed in Žiče monastery, founded in the 12^th century (Minařik 1966, 65) ; but this hypothesis was made on the basis of books on the subject of glass working that were kept in their library. The written sources first mention glass production in Ljubljana as late as the 16^th century (Kos, Žvanut 1994).

4According to the research of the glass material it can be assumed that in the period from the13^th to the 15^th century glass objects came to Slovenia as imports. Products from Italian and Venetian workshops as well as forms typical for German production centres can be found among the excavated material (Lazar 2003, 85). Glass artefacts are dominated by beakers with applied melted droplets, truncated conical beakers, bottles and flasks, as well as some examples of alchemical vessels. The material does not present only vessels for everyday use but also enamelled beakers, a Gothic painted glass window as well as a reliquary in the form of a prunted beaker. The most important finds came from the medieval town of Celje (Lazar 2001, 84) the seat of the earls and later princes of Celje (who played a significant role in the politics of the 14^th and 15^th centuries), and Ljubljana (Kos, Žvanut 1994 ; Petek 2004, 115).

1.1 The variety of beakers

5Truncated conical beakers were an exceptionally widespread form in the Middle Ages. Plain beakers with a pushed-in or strongly concave base are already mentioned under the name of miolo or moiolo at the end of the 13^th century in the archives of the Murano glassworks (Zecchin 1970, 28). Among the material in Slovenia (Celje, Piran and Slovenj Gradec) examples of the bases of such beakers, made of colourless glass and very thinly blown are known, although some rim fragments are decorated with a blue trail, applied on the rim. Artefacts with decorated walls became popular later on. The motifs were most often geometric : rhomboids, circles, zigzags, hexagon or honeycombs, vertical ribbing etc. (fig. 2). The closest workshops that produced these beakers were located in Tuscany in Italy. Archaeological finds and written sources confirm that they were produced in the towns of Gambassi and Germagnana (Mendera 1989, 75). The beakers appear in archaeological contexts from the late 12^th century until the end of the 15^th century. According to Venetian documents, mioli gambassini comprised more than 70 % of Italian production from the mid- 14^th century (Mendera 1990, 310; Newby 2000, 262).

6Beakers with applied melted droplets or prunts are the most typical medieval beaker type. Among the material from Slovenia the prunts vary in size and form. Some take the form of hemispherical convexities, although others stick out like thorns. The beakers were free-blown and subjected to additional working, whilst in a molten state. The thin glass thread, applied below the rim, is made of colourless or contrasting, blue glass and separates the smooth rim surface from the richly decorated body. A glass ring that served as a low foot was put on to the strongly concave base. Numerous parallels for beakers with applied blue trails are known from Germany and France (Foy 1996, 133). This type of decoration appears at the end of the 13^th century and is widespread at the first half of the 14^th century (Baumgartner, Krueger 1988, 275). The Celje material includes two completely extant prunted beakers and a further twenty partially extant examples (Lazar 2001, 89-90 ; fig. 3). However, it is possible to distinguish between the quality of the glass and also by the droplet form. These differences permit the supposition that the beakers came from different glass workshops. The archaeological contexts indicate that colourless prunted beakers were produced from the 13^th century onwards. Their production was not confined to Venice alone, but also took place in the other European glass production centres (Stiaffini 1991, 231). They were most common in the 14^th century, but they were gradually replaced by beakers with larger flatter droplets from the beginning of the 15^th century (Stiaffini 1991, 248). The material from Slovenian sites contains a considerable number of prunted beakers, e.g. at Ormož (Tomanič Jevremov 1997, 107, t. 6:8), Ljubljana (Auersperg Palace, SAZU Courtyard ; Petek 2004, 79), Slovenj Gradec (Lazar 2017, 55) and the above-mentioned Celje (Lazar 2001, 71, n° 18-33).

7The Krautstrunk or cabbage stalk beakers (a literal translation of the German Krautstrunk), beakers with large flat droplets, have so far been found in numerous sites in Slovenia (Lazar 2003, 82). The large flattened droplets are 2 cm to 2,5 cm in diameter, whilst the walls (circa 0,2 cm thick) are considerably thicker than those of the prunted beakers. Some beakers and fragments are made of colourless glass and are more thinly blown (examples from Celje and Piran : Lazar 2004, 27, n° 7), but the majority is made of bluish-green glass with thicker walls.

1.1.1 Reliquary (fig. 4)

8Sometimes these beakers were also used as reliquaries (Baumgartner, Krueger 1988, 336, n° 403, 405-7). The Museum in Nova Gorica (Goriški muzej) has recently acquired such an example, which is at the moment the only find of its kind known in Slovenia. It was bought from a private collector. The beaker is completely preserved, made of bluish glass and has a lid with a well preserved and legible seal. Also acquired together with the beaker was part of the document with an inscription mentioning the years 1470 and 1478 and is linked with Antonio Goppo, the bishop in Trieste1. It talks about the transfer of a relic to the church of St. Brici in Naklo near Divača, a small local church dated to the 15^th century (Peskar 1999, 39-40)2.

1.1.2 Goblet with painted decoration (fig. 5)

9The excavated material from Celje old town centre also includes an almost completely preserved goblet with remains of painted decoration (Lazar 2001, 76, fig. 2). The knopped-stem goblet is made of a good quality thinly-blown glass, has a hollow foot, plain knop and a conical cup. This bears the remains of painted dots in a horizontal band and a coloured heraldic shield with tendril decoration below the rim edge. The remains of white or pink, yellow and red colours are visible. Parallels for the goblet can be found in Italy, where a similar goblet, bearing the coat of arms of the Sforza family, is dated to the end of the 15^th century (Salsi, Mori 1998, 290, tav. XXX), whilst the lidded goblet from Halle in Austria was made around 1550 (Drahotová, Urbánek 1991, 50, n° 24). A goblet from the collection Veste Coburg, bearing the coat of arms of the Praun familiy, is dated around 1550-60 (Theuerkauff-Liederwald 1994, 190, n° 173).

1.2 Bottles and flasks

10Bottles are the most common finds and are known in archaeological contexts from the 11^th century onwards (Stiaffini 1991, 216 ; Ciappi 1991). The most widespread are free-blown flasks with a long neck, which terminates in an upright or slightly everted rim. The neck frequently has a bulge. The body is spherical, pear-shaped or cylindrical. The base is usually flat with a high kick or strong concavity in the centre, although some flasks have an applied high, separately blown foot. Many fragments of simple free-blown bottles are known from the sites and collections in Slovenia. The only decoration is the bulge thickening on the neck (Lazar 2001, 91). They are made of colourless or slightly bluish glass and are very thinly blown. Fragments of these flasks have been found in contexts from the end of the 14^th and the beginning of the 16^th centuries (Petek 2004, 116). Mould-blown bottles are very similar in form to the free-blown examples, the only difference being that the walls are decorated with vertical or diagonal ribs (or channels), whilst some are further decorated also with an applied dark blue glass trail (Lazar 2001, 94, n° 88-105 ; 2003, 86).

11Mould-blown bottles appear from the second half of the 14^th century onwards (Stiaffini 1995, 349). Workshops that produced these bottle types in the 14^th and 15^th centuries are known in northern Italy, in the region of Monte Lecco (Stiaffini 1995, 347).

12Bottles with applied blue trail decoration on the rim or just below it are common on sites from the Balkans to Hungary, Czech Republic, Austria, Germany and France (Baumgartner, Krueger 1988, 275, n° 310 ; Černá 1994, n° 133; Tarcsay 1999, 149), but they are rare in Italy.

13A further common characteristic form is a biconical flask. These flasks were formed by a single free-blown process and other quick, simple processes by the glazier. The fragments of flasks with a ring on the interior of the wall were already known in the 12^th and 13^th centuries (Kosler 1998, 221). The 14^th century saw the final development of the characteristic form with an overarching upper section, which is usually known as the biconical or double conical flask (Baumgartner, Krueger 1988, 316). It appears in a variety of forms throughout Europe, but is virtually unknown amongst the Italian material. German flasks were produced from greenish glass, the lower section being barrel-shaped and on earlier products sometimes completely ribbed (Kosler 1998, 220, fig. 1). The Czech forms were produced in colourless glass with a cylindrical lower section and an overarching upper section, which was arched low over the bend (Černá 1994, 58, n° 41-43). Biconical flasks also appear on the Balkans (Han 1975b, 123, fig. 10) and in eastern France, where they were in use from the 14^th to the 16^th centuries (Waton 1990, 18). The biconical flask form developed from the robust products of the 14^th century to the higher and slimmer forms of the 16^th century, which have a characteristic narrow base surface and an ever smaller ring on the wall interior (Kosler 1998, 224). Their production was most widespread in the German area and continued until the first half of the 17^th century. The flasks and fragments from Slovenia were produced in very thinly free-blown yellowish brown glass. The rims are characteristically stepped, their bodies slim and the bases are strongly concave (Lazar 2003, 87, fig. 5). The characteristic rim form and glass colour lead to the conclusion that these finds may be products of the workshops that operated in Ljubljana in the 16^th century (Kos, Žvanut 1994, 17).

1.3 Stained-glass windows (fig. 6)

14Stained-glass windows are surely one of the most splendid products of the medieval glazier. They were an integral part of the architectural decoration in small churches and magnificent cathedrals of the Gothic period. Few stained glass windows survive in Slovenia, a rare example being the two windows from the church of St. Leonard in Drevenik, which are kept in the Regional Museum Celje (Badovinac 1996, 88, figs. 1-2; Lazar 2001, 80, fig. 3). The church of St. Leonard was probably built in the Romanesque period, but was rebuilt around 1400 during the reign of Friedrich II of Celje (1362-1454). The biphoral window in the eastern wall of the presbytery retained the original lenticular glass with the coats of arms of the Counts of Celje (dim. 43,5 x 33,5 cm). The left hand half contained the coat of arms with two red beams on a silver field (the counts of Žovnek), whilst the right hand side bore the coat of arms with three golden stars on a blue field (the counts of Celje ; Fugger Germadnik 1999, 51).

2 Croatia

15In Croatia research on medieval glass developed recently in Istria and Dalmatia with publications of the latest research results. The Adriatic area is extremely interesting and gives rich archaeological evidence on medieval glass due to numerous shipwrecks discovered along the Dalmatian coast (Gluščević 2006b, 9-16). Archive sources prove the existence of local glass workshops in Dubrovnik from the 14^th century onwards.

2.1 Istria

16The recent publication from 2016 “Temporis signa – Archaeological evidence of the Istrian modern era” brings an overview of medieval and modern glass by Tatjana Bradara (Bradara 2016, 165). Published glass material shows the timespan between the 14^th and 17^th century with the material coming mostly from the Italian workshops, but products from Dubrovnik and Ljubljana must also be included. Archaeological finds do not reflect the extremely high standards that produced the high quality glass ware in the workshops of Venice or Murano. The glass finds from Istria represent mostly fragments of vessels, mostly tableware, made of colourless and sometimes greenish glass (Bradara 2016, 165-166). Some examples of high quality medieval glass are kept at the Mimara Museum in Zagreb, but their provenance is not known (they do not come from the sites in Croatia) since they were part of a private collection (Ratković Bukovčan 2013, 20, no. 1).

2.1.1 Fresco decorations with representation of glass vessels (fig. 7)

17In Istria we also have evidence about the use of glass and glass forms depicted on frescoes. In the church of the Holy Spirit from Bale there is a fresco representing the Last Supper with glass vessels on the table (Bradara 2016, 167, fig. 29). We can recognize simple truncated conical beakers and bottles on high feet with globular or pear-shaped bodies. The fresco is dated to the 15^th century and some authors believe it was painted by Albert of Konstanz (Bradara 2016, 167 and footnote 337). Other representations of glass objects on frescoes are also known from the church of St. Barnabas in Vižinada near Pula (depiction of The Last Supper) and in the church of St. Mary, Škrine near Beram (depiction of The Visitation), both dated to the 15^th century (Bradara 2016, 168).

2.2 Shipwrecks

18The eastern Adriatic coast played an important role in navigation history through most historical periods and it was extremely important for all the ships that sailed along it and connected the Caput Adriae with other destinations in the Mediterranean. In the medieval and modern periods traffic on the eastern Adriatic coast was also very intense. The most important underwater finds and discoveries from the Early Middle Ages to the 19^th century are collected and reported upon by Gluščević (1994, 13-31 ; 2006a, 59-62 ; 2006b, 9-15).

19On the sites of the Adriatic coast there is an abundance of the material from Venetian workshops. Important material came to light from shipwrecks along the coast, mostly dating from the 15^th to the 17^th century, if we mention only some of the best known and published sites (Gnalić : Lazar, Willmott 2006 ; Korčula : Jurišič 2001 ; Koločep : Medici, Radić Rossi 2015). In the last few years the International Centre for Underwater Archaeology in Zadar3 has regularly published the results of their work in their journal Submerged Heritage and has also published the latest finds of post-medieval glass material (Bekić 2014).

20The oldest and very intriguing finds from a shipwreck are known from the island of Mljet – Cape Stoba (Han, Brusić 1978, 273). The shipwreck was documented in the seventies and sailed with a cargo of Byzantine amphorae dated to 9^th to the 12^th century. But a large number of glass fragments were also discovered on the site, together with a completely preserved goblet or footed bowl made in a combination of yellow-greenish and cobalt blue glass (fig. 8), decorated with eyes or circles on the foot (Radić Rossi, 2012, 24, fig. 23-26). Among the remaining fragments there was also a rim of a small bowl made of deep blue and yellow-greenish glass. On the lower side of this bowl is a miniature engraved inscription that could not be deciphered. They suppose it is an alphabet or a form of Aramean writing. This script was developed by several Christian communities in the region of Syria and Mesopotamia and remained in use in the area also after the Arab occupation (Han, Brusić 1978, 273, 281, fig. 4). The luxury glass objects are supposed to be of Eastern origin, either from Islamic or Byzantine workshops and are dated to the 10^th - 11^th century. This is also the period when the presence and the influence of Byzantium on the Adriatic became stronger. The closest comparison for the cargo of the Cape Stoba is the Serçe Limani shipwreck (Bass et al. 2009).

2.3 Local glass production in Dubrovnik

21Some archive sources suggest the glass masters operated in Dubrovnik as early as the beginning of the 14^th century, but their operation can be confirmed with certainty during the 15^th and 16^th century (Han 1973 ; 1974 ; 1975a ; 1977). Talking about Dubrovnik and its glass heritage we have to mention the latest research and publications by Nikolina Topić on the glass material in Dubrovnik and its region (Topić 2015, 490; 2017, 482) and also some analysis of the medieval and post-medieval glass from the area (poster presented at the EXRS in Bologna in 2014). She also presented her work on medieval and post-medieval glass via exhibitions in Dubrovnik and Zadar, the latest being entitled “II Millenium Glass in Dubrovnik Area”4. Additionally, linked with the Adriatic region and Dubrovnik influence, we need to single out the publication about the medieval glass from the cathedral of St. Tryphon in Kotor (modern Montenegro ; Križanac 2001). The city of Kotor is situated in the Gulf of Boka Kotorska, in the immediate vicinity of Dubrovnik. Harboured at the end of a bay, the city has been a seaport and played an intermediary role in the maritime trade between the Balkans and the ltalian Peninsula, i.e. the Mediterranean in general.

22In a well situated near the altar of the cathedral (Križanac, 2001, 9, fig. 2), a considerable quantity of glass fragments was found. The process of reconstruction has yielded 163 vessels, but this is not yet the final number (Križanac 2001, 72). The find includes tableware - bottles and drinking glasses, church lighting devices - icon lamps, and pieces of window glass - oculi. Diverse origins and influences (Italian, Byzantine and Islamic) have been detected through the material (Križanac, 2001, 83). Although the Kotor find includes glassware of varied origin, Milica Križanac supposes that a local, so far unascertained, glass workshop should not be ruled out, at least for some of the vessels (2001, 84). The find is dated from the 12^th to the 14^th century (Križanac 2001, 83).

3 Bosnia and Herzegovina

23In Bosnia and Herzegovina the medieval glass material shows influences of Italian, Venetian, Bohemian and German production centres (Han 1975b, 114; Wenzel 1977, 75). The glass finds came mostly from the sites of monasteries and castles such as Kraljeva Sutjeska, Veličani, Biskup Konjic, Castle Ščepangrad, Castle Bobovac etc. Kraljeva Sutjeska, a Bosnian royal residence from the second half of the 14^th century until the mid15^th century yielded a great quantity of medieval glass (Kojić, Wenzel 1967, 80). There are also some forms among the material that can be ascertained as the local glass style, but the production centres are still questionable. M. Wenzel suggests that some typical forms like cupped-rim beakers, often ribbed and decorated with blue threads around the rim may have been produced in Venice for the market in Bosnia and Herzegovina (Wenzel 1977, 63, fig. 1). This particular style of glass (fig. 9) is found in great numbers in Bosnia, in lesser numbers in Serbia and ascertained nowhere else (Wenzel 1977, 64). Unfortunately in the past decades there has been no new research on Bosnian medieval glass. So we can only single out some questions that arose during the research of the medieval glass in the 70s and 80s.

24Some forms can be singled out that are presented in great quantities, the cupped-rim beakers, prunted beakers and krautstrunks. The forms and details show some Venetian, and strong German and Bohemian influence. But most probably the forms for this market were made and copied outside Germany and Bohemia. They are made of clear glass, with a grey tinge. It is possible it was produced in Italy for the use of the non-Italian and German oriented market, but it is also possible that these are the products of closer Dubrovnik workshops, active in the period in which the Bosnian glass was presumably made (Wenzel 1977, 73). The question arose as to why Bohemian and German taste is so strong in this area. Some historians suggest this may be linked with Saxon miners, who arrived in Bosnia and Serbia from the 14^th century onwards. From the period of the Serbian king Uroš I. (1242-1246) and later they reopened the metal mines in the area, which were abandoned after the Roman period. This brought a strong impulse on the economy of the area. Also the Saxon miners were well paid technicians, accustomed to the luxury commodities from their homeland, such as glass vessels (Wenzel 1977, 75). It can be assumed they commissioned them to be made, either by local forest glass makers or passing traders from Dubrovnik.

25Some glass analysis made decades ago suggests traces elements in this glasses are similar to Roman and Byzantine glass and that this is soda-lime–silica glass (Wenzel 1975, 211).

26So no exclusive place of origin for these Bosnian glasses is known, which show mostly German design and taste. Some examples may have been made in Venice, Dubrovnik, perhaps in Serbia, while others may have been the products of local forest glassmaking (Wenzel 1977, 76). There are still numerous open questions and at the moment also a lack of researchers and interest to study medieval glass in Bosnia and Herzegovina.

Conclusion

27At the end of this overview we may conclude, that in the research and analysis of the medieval glass in Slovenia and the Balkans there are numerous open questions and a break in research is evident for some areas. There is a need of collaboration and would be important to establish and develop new and long lasting links in this research. A crucial role and part can play universities to educate and raise young people with the interest for the study of the medieval glass as a material culture, as well as museums with material stored in their depots. It would also be important to start with workshops and scientific meetings to exchange our knowledge and information about ongoing projects. The latest is at the moment perhaps the best way to bring first new results that would be available to the research audience in the area in question and worldwide.

Figures

Fig. 1 - An overview of the principal forms of medieval glass in Slovenia (after Lazar 2003).

Fig. 2 - Truncated conical beaker with ribs from Celje, Slovenia (photo Tomaž Lauko).

Fig. 3 - Prunted glass beaker made of colourless glass, Celje (photo Tomaž Lauko).

Fig. 4 - Reliquary from Naklo near Divača, Slovenia.

Fig. 5 - Goblet with remains of painted decoration, Celje (photo Tomaž Lauko).

Fig. 6 - Two glass windows from Drevenik, Slovenia (photo Tomaž Lauko).

Fig. 7 - Frescoe from the church of the Holly Spirit from Bale in Istria, Croatia.

Fig. 8 - Glass bowl from Mljet – Cape Stoba, Croatia (after Radić Rossi 2012).

Fig. 9 - Cupped-rim beaker, ribbed and decorated with threads, Kraljeva Sutjeska, Bosnia and Herzegovina (after Wenzel 1997).