The Glass from the Gnalić Wreck, Croatia
University of Sheffield, UK & University Primorska, Koper, Slovenia
In 1967 a shipwreck was discovered by the rocky islet of Gnalic, at the entrance to the Pašman channel, just to the south of Biograd, Croatia . Between its discovery and 1996 six campaigns were organised to recover portions of the vessel its cargo. It was soon realised that the wreck was a late 16th-century merchantman, which had sunk with its cargo intact. The most numerous amongst the goods being transported were items of glass, and even though only a relatively small area of the wreck has been completely excavated, over 5,500 vessels, windows and mirror plates have been recovered. As such it is the largest assemblage of post-Roman glass to have ever been recovered from a single context.
Shortly after the initial discovery of the cargo, many of the more diagnostic pieces were exhibited in several locations in the former Yugoslavia , until the whole collection was deposited in a specially design museum, where they can still be seen today. However, despite some initial interim reports, the glass was never comprehensively studied or published.
During summer 2005, as part of the wider Heritage of Serenissima project investigating Venetian influence in the Adriatic, a team of English and Slovene archaeologists undertook the first systematic analysis of the glass. The aim was not only to classify and accurately quantify the glass for the first time, but also to answer a number of specific research questions. Since its discovery it had been widely assumed that the ship was a Venetian galley and therefore the likely origin for all the glass was Murano. However, this supposition was open for questioned for the first time. Furthermore, it had never been established where the glass cargo might have been heading, or indeed whether it was destined for a single place, or represented the contents of a ship that was stopping to trade at a variety of Adriatic ports. Only detailed examination of the glass could start to answer these important questions.
The largest category of glass found consisted of vessels (in excess of 4,000 individual items) and these were predominantly tablewares. These included vessels decorated with exceptionally high-quality and detailed diamond-point engraving. Their consistent style and the repetition of identical motifs, suggests that these were the product of a single workshop, and it is indeed likely that this was Venetian. Other forms were of a less certain provenance. Some, such as a group of lidded tankards may have been produced in Italy but for a foreign market. However, these constitute only a small portion of the total assemblage. The largest group of drinking vessels, and with over 3,000 examples were goblets with a folded foot and either plain or mould-blown bowls. The poorer quality of the glass of these vessels, as well as their often careless construction, suggests a more provincial manufacture, and it is possible they originated in Dubrovnik , which was known to have its own industry at this time.
The mirrors found were all made by a more laborious process, to ensure that the glass was of sufficient flawless quality to reflect without distortion. A thick sheet of glass was first cast into the approximate shape and once cooled its surfaces were ground smooth. Contrary to popular belief silver was not used to make them reflective, rather an amalgam of tin and mercury. Amazingly this remains on some of the examples from Gnalic, but what is also interesting is that it is apparent that unground and unfinished mirror plates were also being transported presumably for retail and final preparation elsewhere.
Whilst the vast majority of the vessels could be shown to belong to a relatively few well-defined categories, there were some smaller groups of glass which were much more unusual. Perhaps one of the most interesting of these was a number of coloured oval bottles and shallow small bowls that were distinctly un-European in style. The most striking of these were decorated with blobs of coloured glass which were `marvered' or smoothed into their surfaces. Plainer, but no less unusual, were over 40 examples of plain blue oval flasks with a distinctive `stepped' rim. All of these vessels cannot be paralleled by examples from known centres of Western European glass production, and at this stage it seems most likely that they were Islamic in origin, although their presence, albeit in relatively small numbers, on what had been previously assumed to be a Venetian galley is curious. Certainly they confirm that the cargo consisted of a more complex mixture of vessels that originally first thought! As well as vessel glass, over 750 circular window glass `crowns' were found. As well as nearly 600 circular and rectangular mirror glass plates. The window glass was made by blowing and opening out a bubble of glass on the blowing iron, and then spinning it so the centrifugal force created an even-shaped disc. In Mediterranean regions these were usually made quite small, such as the Gnalic examples, and incorporated into glazing pattern whole, but would have only been used in churches or the more wealthy households.