Museo Correr

Museo Correr

THE ADVENTURE OF GLASS. A millennium of Venetian art

From the beginning to the 15th century

In the year 982, for the first time in a Venetian document – a deed of gift to the Benedictine Church of San Giorgio Maggiore – we find a reference to the existence of a glazier: his name was Dominic. This ancient manuscript is considered the birth certificate of glassmaking in Venice. Advancing into the late Middle Ages, reports of the presence of such production in the city become more numerous and give an image of a flourishing industry that gradually became one of the most important for the Serenissima. The nerve centre of the activity was then concentrated in Murano, where the glass foundries had begun to establish themselves in the second half of the 13th century. In fact, the Grand Council, in 1291, decreed the transfer of the furnaces to outside the city’s urban core to avoid the risk of fire. Since then glass has been an abiding presence in Murano that still continues today. The glassmakers in medieval Venice were called fiolari, meaning manufacturers of fiole i.e. bottles. These craftsmen were thereby identified by the kind of things they made, and certainly the bottle was one of the main products of the Murano glassworks. The so-called inghistera or angastaria (from the Greek Gastra = belly and aggoz = vase), with a long neck and a body expanding at the base, was at that time considered the bottle par excellence. Various models were differentiated by the form of the mouth, the shape of the body and the type of base; if they were decorated, it was with simple spiral motifs or vertical ribs created with a mould. Glasses, as well, were produced in great numbers. The simplest ones were cone-shaped or cylindrical, with a flat base, without ornament or with small geometric motifs in very low relief that was sometimes hardly noticeable unless seen against the light. They were sometimes decorated with a blue filament around the rim. But there were also more elaborate models, like the original glasses decorated with large or small glass drops. The latter, in particular, referred to in fifteenth century Venetian documents, were intended largely for the German market where similar products were widespread. In the late medieval period, therefore, an important part of production was made up of objects for the table; it is not by chance that necks and bases of bottles and fragments of drinking glass are the most numerous glass artefacts recovered from the lagoon area. Goblets and bowls, however, were counted amongst the most valuable objects and, consequently, are more rare in archaeological findings. Many other articles as well – impossible to list exhaustively – testify to the vitality and variety of production in medieval Murano. They produced, for example, numerous varieties of rui, the famous circular glass windowpanes, which still can be seen today in Venetian palaces. For lighting they made oil lamps, in one or more varieties, placed in special metal supports to be suspended from the ceiling. There were different types, but one in particular seems to have been adopted by preference in Venice: the lamp of Islam, in imitation of oriental models used in mosques. In addition, by command of the Serenissima, the Murano glassmakers were required to produce weights for scales and bottles for taverns (for accurate measurements) that were stamped one by one with the symbol of the city, the Lion of St Mark, to confirm their validity. One particular product was a component for textile looms, a kind of bearing that, being glass, ensured greater resistance to wear than other materials. The range of production and the quality of the Murano glass industry in the late Middle Ages was, therefore, very broad and diversified. For the production cycle they used two types of furnace in Murano. The first, called a calchera, had two levels. In the lower level was the fuel, which until the 19th century was wood, while the upper part was used for the initial fusion of sand or ground pebbles, to which was added a flux to facilitate melting. From this first phase was obtained the so-called frit, a solid mass, which was then ground down to be introduced into another furnace where the production cycle was completed. This second furnace had a circular form with three layers. In the lower part was the fuel, which heated the median level where the glass was fused definitively in specific containers, crucibles, which held the frit and the rubble. The third level was used to store the finished products and allow them to return gradually to room temperature, thereby avoiding fractures caused by cooling too quickly. The process that led to the production of a glass object was long and complex, but the old Murano glass factories were able to achieve great results that, thanks to the contribution of archaeological research, we can still see today in the first section of the exhibition. The greatest revolution in the history of glass – the discovery of glass blowing – is usually thought to have started around the middle of the first century BC, somewhere along the coast of the eastern Mediterranean. It is difficult to determine how they arrived at this procedure; the sources are silent and there is a paucity of archaeological data relating to the earliest blown glass. New light was thrown on this issue at the excavations in the Jewish Quarter of Old Jerusalem, where the glass relics appear to be the oldest known blown glass products, dating to the first half of the first century BC. The process of blowing through pipes, however, was considered a preliminary stage to the invention of the blowtube, or at least a contemporary alternative method, inasmuch as the artisan, perhaps to increase inflation, inserted a metal rod into the glass tube where the vitreous mass was ready to be shaped into a precise aesthetic definition. Among the free-blown products, in both the Correr and Manca collections, special processing characteristics and/or decorations are present, which are useful to highlight, specifically examples where there is a decoration achieved by the application of hot glass threads, often in relief. These pieces, in fact, sometimes display more than one winding spiral of glassy filaments. Handles were also applied hot to those objects that required them, either as loops, or pseudo loops of pinched glass.