Glasswork in Early Renaissance Italy

Roughly between the years 1300-1500, the production and artistry of glasswork in Italy grew, along with many other innovations and ideas that later came to define the “Renaissance” period, specifically on the Italian peninsula. Although artistic and utilitarian creations made of glass have their origins millenia earlier than this period, combinations of technological innovations, global impacts and influences, and higher rates of production, make this period worth defining. The features to follow demonstrate various impacts on, and attributes of, glass work in Italy, including Islamic material and stylistic traditions in Venice, post-Gothic stained glass innovations in Florence, pigment mines local to Italy, Silk Roads works from China, pigments from Egypt, and more. Collectively, these objects, materials, and techniques explore the global reality of the Italian Renaissance; a time commonly thought of in isolation, rather than dynamic in the collaborative world the period lived in. 

The city of Venice, since the Medieval establishment of the Silk Routes, has been a hub for cross-cultural trade and growing industry. These traits can be attributed to Venice’s prime location as a port city, nestled in on the Mediterranean sea, creating a center to connect trade between western Europe and the near East. Although numerous industries, both artisanal and otherwise, were home to Venice during this period, glass remains one of the most famous. Glasswork in this city grew from cross-cultural traditions of material and techniques, into a unique amalgamation combined with local traditions. Venetian glass became one of the Italian peninsula’s most notable crafts. Glassmakers found the island of Murano to be an unlikely location for their craft, as feeble amounts of quality sand and deposits of other minerals were of access. Glassmakers also needed access to large amounts of wood for firing their glass, which both Murano and Venice had little supply. This created a demand for imported material goods to support the growing glass market. Despite the unfavorable material location, Murano island was used for glass production in an effort to prevent the risk of kiln fires on the main island of Venice.

Millefiori, meaning “thousand flowers,” defines a glassmaking style and technique that is characterized as a type of mosaic, and appears in a variety of flower-like patterns. The process originated in Ancient Egypt around 1400 BCE during the New Kingdom, when glassmaking came into Egypt through Mesopotamia. The popular technique became a tradition as it spread to Alexandrian craftsmen around the second century BCE, and finally adopted by artisans in the Roman Empire about one century later. Millefiori continued being practiced throughout the Medieval Period on the Italian peninsula, and was then refined by Venetian artisans during the fifteenth century. Within Venice, a majority of Millefiori works were created on the island of Murano, which is known for its talented artisans and vibrantly colored glass. 

Millefiori was made by organizing threads (long pieces of rolled out glass) of glass into the desired design, usually floral, and then fused together at extremely high temperatures. Once the threads are molded together, they can be further shaped into beads, or cut and organized to create other works such as popular salt cellars. As Edwin Barber describes in his article “Mosaic and Millefiori Glass," Murano glass, including Millefiori remains famous for its use of vibrant glass, which was made using ground pigments often imported into Venice from Egypt and other areas of the Near East. Because of the intricate and highly detailed process for creating Millefiori pieces, the practice was revered in Venice, and often represented wealth. So much so that Millefiori beads became a form of currency throughout Venice, as well as other areas of Europe and into North Africa. This currency aspect of the glass works was not a purely Renaissance convention however, it happened in different regions during different time periods, but remained true throughout the Renaissance as artisanal products were being refined, and industry was ever-growing. 

Barber, Edwin A. “Mosaic and Millefiori Glass.” Bulletin of the Pennsylvania Museum 13, no. 51 (1915): 31. https://doi.org/10.2307/3794267.

The material composition of glassmaking requires what’s called a “former,” or the element that forms the glass itself, and is usually silica. By the mid 1400’s, raw minerals containing silica were predominantly imported from sites along the Swiss Ticino river, and the Italian Adige river, and were ground into powders by the Venetian glassmakers. Along with the “former,” glassmaking also required a “flux,” used to moderate the silica’s melting point, was made from plant ash, which was imported into Venice from Syria and Egypt beginning in the 1200’s, and later Iberia and Sicily. The finished “flux” was called soda di Catania. Additionally, glass composition also requires a “stabilizer,” used to create a durability and water resistance in the glass. Alumina, magnesia, and lime are the main stabilizers found in Venetian glass works, which contributes to their survival. Finally, “decolorizers” were used to decrease, and sometimes eliminate the discoloration caused by iron and sulfur. Most often used to achieve this is manganese dioxide, which was imported from the Piemonte region of the Italian peninsula beginning in the late 1200’s. It is worth summarizing that many of the foundational compounds used for glassmaking were imported from several outside regions and nations, many of which with a rich history in glassmaking. This piece, cristallo (clear), exemplifies the degree to which Venetians mastered the creation of colorless clear glass that had enough durability from the other compounds to last for centuries.

Dillon, Sarah M. Seeing Renaissance Glass: Art, Optics, and Glass of Early Modern Italy, 1250-1425. New York: Peter Lang, 2018.

Lattimo glassware, originally attimum, describes what today is referred to as milk glass or porcelain glass. Lattimo began with its inspiration from Chinese porcelain glass, which was introduced to those from the Italian peninsula during the Medieval period along the Silk Routes. In the later Medieval and early Renaissance times, Venetians took great influence from such glassware, and formulated their own imitation glass known as lattimo. These glassware items made in Venice were of high value, and most often used as matrimonial or diplomatic gifts, as well as being adorned with religious imagery. The imitation glass was created by adding tin oxide crystals (cassiterite) to foundational glass composition recipes, which gave the glass its opaque, milky appearance. This piece of lattimo served as a marriage beaker, likely a gift, which also exemplifies connections between artisanal industry and the use of artisanal objects in domestic settings.

Gong, Xue, Zhongqu Xie, Xiangyu Liu, and Bianca De Divitiis. “Cross-Cultural Encounters: Religious Motifs in Lattimo Glass from China to Italy.” Religions 14, no. 7 (2023): 932. https://doi.org/10.3390/rel14070932.

Gudenrath , William. “Glass as a Material in Renaissance Venice.” The Techniques of Renaissance Venetian Glassworking, Corning Museum of Glass, 2016. https://people.cmog.org/bio/william-gudenrath.

Kelly, Jessamy. “Imitate: Remediating Glass as an Artistic Medium for Material Imitation.” Arts 8, no. 1 (2019): 30. https://doi.org/10.3390/arts8010030.

In her article "The shipwreck of gnalić, " Irena Rossi delves into the shipwreck of Gnalić, a Venetian shipwreck from 1583 that was found in the Adriatic sea off the coast of the island of Gnalic (contemporary Croatia), after sinking on its voyage to Constantinople. The ship’s load contained pigments more than anything, which would have been used for tapestry dyes, leather, spices, and of course glass. These pigments included lead carbonate, lead oxide, mercury sulphide, lake, tin, and iron oxide-based coloring agents, and vermilion among others. This is possibly a fragment of vermilion, which would have been of high expense and produced a deep red hue.

Rossi, Irena Radić, Mariangela Nicolardi, Mauro Bondioli, and Katarina Batur. "The shipwreck of Gnalić", 2021. https://doi.org/10.2307/j.ctv289dp9c.

Throughout the city of Florence, glasswork grew in production predominantly in the fourteenth century, despite its region of Tuscany establishing its first glass workshop in the 12th century. Florentine glass primarily consisted of stained glass pieces created for church architecture, as well as smaller domestic glassware. This theme remained relatively consistent between Florence and other areas of the peninsula, including Assisi and Siena with their notable contributions to early Renaissance stained glass in prominent chapels (i.e. Siena Cathedral, and the Saint Martin Chapel in Assisi). Florence conducted a majority of its art production through guilds, though the city did not have a guild for glassworkers, and instead worked with the craft associations. The introduction of glass into Florence is often accredited to trade and influence from Venice or southern France. 

Near the altar space in the Santa Croce Basilica, these stained glass windows being long attributed to Giotto (b. 1260s or 70s. d. 1337), the panes were later attributed to Master of Figline (b. 13th century. d. 14th century), who worked on later works in Assisi as a painter and glass-glazer. Figline’s work as a painter shines through his glasswork, as fine-stroke glazing on these windows closely resembles painting techniques used in the fresco painting process. The panes were layered with glaze in particular manners to achieve specific hues desired by the artist, an example of which includes a green glass piece made of six alternating layers of blue and yellow. Many of the other panes would have been pre-made in glassmaking workshops, and later cut and used to create specific pieces that the project demanded.

Staley, Edgcumbe. Guilds of florence: With bibliographical and chronological tables. New York , New York: Nabu Press, 2010. 

Lane, Arthur. “Florentine Painted Glass and the Practice of Design.” The Burlington Magazine 91, no. 551 (1949): 43–48. http://www.jstor.org/stable/870030.

This stained glass oculus window, located in the Basilica della Santissima Annunziata (Basilica of the Most Holy Annunciation), was crafted by artist Alessio Baldovinetti (1427-1499) in the 1460s under the commission of Piero di Cosimo de’Medici (“The Gouty”). This piece, the first glasswork piece installed in the basilica, displays numerous connections between Florence and Eastern Mediterranean societies. Specifically, the Mamluk Sultanate of Egypt script known as Thuluth, the pseudo-script has an inscription band around the peramitor of the oculus. Knowledge and incorporation of the script alludes to a high degree of political power of Piero, as his cross-cultural connections display his reach and power in association with Levant rulers and churches. This attribute is amplified through the larger inclusion of Piero’s coat of arms being the central design of the oculus. Although this piece has little material analysis, it exemplifies connections between cross-cultural interactions and glasswork. 

Cavallo, Bradley J. “Of Medici and Mamluk Power: Islamic Forms in a Renaissance Florentine Stained-Glass Window.” Viator 45, no. 1 (2014): 311–30. https://doi.org/10.1484/j.viator.1.103793.

Duccio's (d. 1319) stained glass window similarly exemplifies a painterly approach to producing stained glass imagery, which blended the gothic style of France, with fresco traditions of the Italian peninsula. In her book Seeing Renaissance Glass: Art, Optics, and Glass of Early Modern Italy, 1250-1425, Sarah Dillon makes these connections between French gothic stylistic traits and Italian fresco traits. In material detail, in Duccio's composition, he used larger cutouts of glass, melding them together using lead, which he designed to fit the large scale of the oculus. This detail remains noteworthy given the trends and traditions in stained glass, which generally uses smaller pieces of glass to create smaller details in the design’s imagery; which further exemplifies the composition’s adaption into Italian design demands, from those of the French gothic. This piece not only reflects cross-cultural exchange of style, but local adaption as well as local use of pigment materials. Duccio and many other late Medieval and Early Modern artists used earth pigments, predominantly sienna, much of which was obtained relatively locally. 

Dillon, Sarah M. Seeing Renaissance Glass: Art, Optics, and Glass of Early Modern Italy, 1250-1425. 43-47 New York: Peter Lang, 2018.

This Florentine roundel, although unattributed, resembles the previous Medici oculus in its composition consisting of a central coat of arms design, framed by laurel leaves. Laurel leaves in coats of arms often find association with integrity and virtue, attributes often desired by those with the coat of arms. Although this piece dates slightly later than those previously stated (1300-1500), it still exemplifies the same objectives, which include both broad and narrow observations of glass's materials, techniques, and purposes on the Italian peninsula. Being made slightly later determines its creation during a slightly more established world of glass making in Florence. This roundel likely used the same, or similar pigments as prior Florentine works, as well as the visible painterly appearance of the design itself, which goes back to the early 14th century and its stylistic integration of French gothic stained glass, with Italian fresco traditions. In summation, this work reinforces the primary points made in regards to Tuscan and Florentine works seen in previous examples.

Conclusively, glass making on the Italian peninsula finds its material, technical, and stylistic origins from across the globe. From France and Egypt, to Syria and China, as well as locally, different attributes that grew the craft over centuries stemmed from a variety of different cultures and their traditions. Seen as Venice (and Murano island), and Tuscany (primarily Florence and Siena) remained the glass-making hubs during the two-century timeline this research has covered, it stands worth noting that the ways in which glass as an international craft varied. Venice, as a cross-cultural port city for centuries prior to this period, welcomed new materials, techniques, and styles into the city, and refined them into what grew to be the internationally renowned glass-making hub. Florence and other Tuscan cities on the other hand, found a majority of their glassworks under the conditions of wealthy patronage or religious architectural commission, making stained glass its prominent tradition. While integrating stylistic attributes coming in from French gothic influence, Tuscan cities implemented their own works with a fresco-like technique, using more visible brush strokes during glazing, and working on large segments of glass as fresco artists would do on plaster (many glazers were also fresco painters). In summation, in regards to material, technique, style, and purpose, the Italian peninsula remained a hub for collecting, integrating, and refining their craft in ways that have impacted the centuries to follow. 

Bibliography 

Barber, Edwin A. “Mosaic and Millefiori Glass.” Bulletin of the Pennsylvania Museum 13, no. 51 (1915): 31. https://doi.org/10.2307/3794267.

Cavallo, Bradley J. “Of Medici and Mamluk Power: Islamic Forms in a Renaissance Florentine Stained-Glass Window.” Viator 45, no. 1 (2014): 311–30. https://doi.org/10.1484/j.viator.1.103793.

Gong, Xue, Zhongqu Xie, Xiangyu Liu, and Bianca De Divitiis. “Cross-Cultural Encounters: Religious Motifs in Lattimo Glass from China to Italy.” Religions 14, no. 7 (2023): 932. https://doi.org/10.3390/rel14070932.

Gudenrath , William. “Glass as a Material in Renaissance Venice.” The Techniques of Renaissance Venetian Glassworking, Corning Museum of Glass, 2016. https://people.cmog.org/bio/william-gudenrath.

Kelly, Jessamy. “Imitate: Remediating Glass as an Artistic Medium for Material Imitation.” Arts 8, no. 1 (2019): 30.  https://doi.org/10.3390/arts8010030 .

Lane, Arthur. “Florentine Painted Glass and the Practice of Design.” The Burlington Magazine 91, no. 551 (1949): 43–48. http://www.jstor.org/stable/870030.

Rossi, Irena Radić, Mariangela Nicolardi, Mauro Bondioli, and Katarina Batur. The shipwreck of Gnalić, 2021. https://doi.org/10.2307/j.ctv289dp9c.

Staley, Edgcumbe. Guilds of florence: With bibliographical and chronological tables. New York, New York: Nabu Press, 2010.