Glass is ever-present in the world around us. As a material, it is ubiquitous in the modern world, from windows and lightbulbs to eye glasses and touch screens. Although it may seem like glass is a modern-day material, that is actually far from true. In fact, glassmaking was first developed thousands of years ago and perfected in ancient Rome. Few materials have stood the test of time in quite the same way. Remarkably, glass is still handmade using those same ingredients and techniques that were used over 2,000 years ago.
Ancient glass offers us important insight not only into how this important industry formed and developed, but also into the lives of those who used the material so many years ago. Read on to learn more about the extraordinary world of ancient glass.
Early Forms and Emergence of Glass
Glass-like materials that are naturally formed were widely used by Stone Age societies long before the technique to make glass was ever discovered. Obsidian, a volcanic glass, was chief among these. Obsidian was processed in a variety of ways. Not only was this material used to make weapons like spearheads, but craftsmen also created decorative objects, jewelry, and mirrors out of this versatile glass-like material. Only found in volcanic areas, obsidian objects became heavily traded throughout the ancient world. Modern-day research into these artifacts offers us insight into the complex trade routes and networks that existed thousands of years ago.
When And Where Was Glass First Created?
So just how and when did the techniques of glassmaking first emerge? Unfortunately, the exact when and where is information that we may never know. Some believe it first emerged in Mesopotamia around 5000 BC, approximately the same time a new material called faience was developed. In his Naturalis Historia (Natural History), Pliny the Elder also dates the origins of glass to this period, but claims it was discovered by Phoenician merchants moored on the river Belus near modern-day Israel. He recounts how these men “accidentally” discovered the art of glassmaking after making a fire on a sandy beach to cook a meal. The flames, Pliny claimed, burned so hot they melted the sand beneath them, creating a river of melted sand that cooled into glass. Though we know today such a scenario is impossible, the story contributed to the local lore of Ptolemais, an ancient site renowned for its glassmaking.
Most scholars agree that the first glass objects date to 1,500 years later - around 3500 BC in Mesopotamia. These objects, primarily beads, were developed from the same materials that were once used to make glazes on ceramic pots and vases, and they were quickly spread throughout the region - particularly to Egypt - by merchants and traders.
The History of Ancient Glassmaking
Glass is remarkably difficult to produce - it requires high temperatures the order for its materials to melt and fuse. Then it must be worked while still molten and cooled slowly to prevent cracking. Due to this difficulty, the earliest glass was a rare luxury. Thus, it was made almost exclusively for the Egyptian royal courts by palace craftsman, and their recipes and techniques were a closely guarded secret. It wasn't until the seventh century BC that the first known written documentation of ancient glassmaking was produced. These Mesopotamian cuneiform tablets from the library of King Assurbanipal (668-627 B.C.) record glassmaking techniques going back to 1300 BC, and describe not only the ingredients necessary to produce glass, but also details tips to ensure success - ritual sacrifices, special purifications, and the days most favored by the gods to work the kiln.
While the earliest known glass creations were simple beads, the glass industry soon developed new techniques to create the type of glass objects we know today - cups, bowls, pots and more. These were first made using the core forming technique, which developed around 1500 BC. In this method, a core was created from clay in the approximate shape of the desired glass object, and is then attached to the end of a metal rod. From there, molten glass was wound around the core material in order to create the shape of the vessel. The glass was then slowly cooled and the core removed to complete the piece.
Core-formed glass was made in a variety of colors during this period. Because so many pieces were made exclusively for the royal family, semi-precious stones such as lapis lazuli and turquoise were ground and added to molten in glass in order to produce vibrant colors. Thus, early glass was sometimes referred to as “artificial stone” or “lapis lazuli from the kiln.” Today, it is still widely admired for its exceptional finish and luminous color.
Glass and Ancient Rome
After the fall of the Bronze Age empires in Greece, Mesopotamia and Egypt, the production of glass temporarily came to a centuries-long halt. It wasn't until around 900 BC when the practice reemerged, and by 600 BC glass was back in full production. Though by this time glass objects from Mesopotamia had spread throughout the Mediterranean and made their way to Etruria (modern Tuscany) and Magna Graecia (areas of southern Italy), these objects have not been found to any large extent in central Italy or Rome. This lack suggests that the Roman glass industry developed quite independently - and quite rapidly - in the region during the first century AD.
Undoubtedly, Rome's place as the dominant economic and military power helped to attract craftsman from other regions, some of whom would have helped introduce the art of glassmaking into the region. It helped that there was no lack of patrons, wealthy or otherwise, to purchase glassware. It was also during this period - a time of great industrial development in Rome - when the glassmaking industry would experience its most important and greatest technical advancement: glass blowing.
While early Roman glass carried on the traditions and decorative tastes of the Hellenistic period, the discovery of glassblowing dramatically changed both how glass was produced and its decorative forms. The new technique is nearly identical to the glass blowing process still used today.
Two ingredients were used in the glassmaking process: sodium carbonate and silica. In order to get the silica to melt at a lower temperature, Roman glassmakers would add sodium carbonate to lower the ingredients' melting point. They would also add a stabilizer ingredient such as magnesia or lime to finish the mixture. If the craftsmen wanted to make a colored glass, they could add a coloring agent or other minerals before finishing their final product.
Then, a piece of molten glass was inflated into a bubble using a hollow metal blowpipe, and that bubble was manipulated to take the desired shape. Glass could also be blown into a wooden or metal carved mold, so the final shape of the glass piece was determined by the interior shape of the mold, not the skill of the glassmaker.
It is unclear which of the glass blowing techniques were introduced first, but both were widely used by the first century AD. Glass became far more translucent; the bright colors and intricate patterns of core-formed glass were abandoned in favor of thinness and transparency. Suddenly, a far wider range of forms and styles could be created by glassmakers, and in a far shorter amount of time.
Types of Glass Objects
With glass blowing, glass objects became far easier and more inexpensive to produce, and thus they could be found in most homes throughout the Roman empire. Many gave up their ceramic drinking vessels in favor of glass. Wine and other goods were shipped, stored and served from glass bottles and jugs. Perfumes and essential oils were held in diminutive glass bottles. Even glass window panes emerged in the late 3rd century AD. Just like today, glass was used in almost every aspect of daily life in ancient Rome.
The most commonly found glass objects that are uncovered today are glass alabastra, unguentaria, and other small bottles. These vessels were used to hold the spices, perfumes or medicines that were so integral to Roman life, and thus they were used by nearly every individual in ancient Roman society. The bottles were made in nearly every shape and size imaginable, from short and bulbous to tall and thin, and many were decorated with engraving, cold painting, or gilding. Applied threads of glass were the most common form of decoration, made from heated rods of glass that were quickly laid onto an existing glass object. Different colored threads were laid down in rows, spirals, zigzags and other optical patterns to create elaborate decorative effects.
Glass was also widely used in jewelry as a less expensive alternative to precious and semiprecious stones such as emerald, lapis lazuli, rock crystal, garnet, and amethyst. Shards of glass were made into elegant necklaces, earrings, bracelets, or pendants. Since Roman glass varies significantly depending on a variety of factors, each piece of jewelry is completely unique with its own coloration and design.
Not only were glass beads highly popular, but also intricately formed glass cameos and intaglios. These could feature any number of figures or symbols, though most popular were figures of the gods. The draped figure of Venus, the ancient god of love, has been discovered on ancient Roman intaglio, while Athena, the goddess of wisdom and war, and Hercules were also popular figures.
Colors of Glass
As we all know, glass made using the purest materials is naturally translucent in color. As we have already covered, glass was made using just two ingredients: white silica sand and soda ash. Yet, sometimes the silica sand possessed natural impurities, such as iron or manganese, which gave the resulting glass a tinge of color. The presence of iron resulted in glass with a green hue, while manganese produced pink- and violet-tinged glass. Thus, many ancient glass objects possess some color.
Of course, many glassmakers deliberately added minerals during the glassmaking process in order to achieve different hues for decorative effect. We already discussed how materials like lapis lazuli were added to create blue glass that rivaled the beauty of any semiprecious stone. Yet, lapis lazuli was so highly prized it was rarely used to color everyday glass objects by this period. More commonly, cooper was added to achieve a blue hue.
Today, three colors are the most sought after in ancient Roman glass: amber, purple and cobalt blue. These colors required complex chemistry and considerable expense to produce, making these pieces even rarer.
Iridescence in Roman Glass
Perhaps one of the most fascinating physical characteristics of ancient glass, however, is a phenomenon known as iridescence. This effect is not a result of a glassmaker's technique or his materials, but rather simply the passage of time. Over the centuries, the natural weathering of glass causes its thin layers to slightly separate from one another and flake away, leading to a refraction of light between each layer. The result is a prism effect created by bouncing rays of light, producing an iridescent appearance.
Iridescence in ancient glass is highly prized. For one, it is a visual indicator that the piece had, in fact, been in the ground for a couple thousand years before it was discovered. In this way, it helps to confirm authenticity. Yet, it also is a breathtaking visual effect. The rainbow-like color changes from every angle, resulting in a piece that is visually interesting as well as culturally significant.
Lasting Influence of Ancient Glass
As ancient glass remains highly collectible, it has naturally influenced a number of makers in more modern history. The most famous of these is, perhaps, Louis Comfort Tiffany. Inspired by the fluidity and iridescence of ancient Roman glass, Tiffany produced blown glass, which became known as "Favrile," between 1892 and 1928. This line boasted pieces of superior quality, renowned for their opalescent and iridescent colored finishes. Unlike ancient Roman glass that achieved iridescence through a prism effect, the distinctive coloring of Tiffany's Favrile glass was ingrained in the glass itself. These pieces were so highly popular and visually stunning that Tiffany won the grand prize at the 1900 Paris Exposition for his creation.
While Louis Comfort Tiffany ingeniously recreated the aesthetic effects of ancient glass, the forms of ancient glass have also frequently been replicated. Perhaps the most highly replicated example is the legendary Portland Vase, an ancient Roman cameo glass vase that dates to between AD 1 and AD 25. The original Portland Vase was discovered in the tomb of the Roman Emperor Alexander Severus in the 16th century. It was later held by the Barberini family in Italy for more than 150 years, and then came into the possession of Sir William Hamilton, who brought it to England. Since then, the vase has been recreated in glass, porcelain, bronze, and a range of other materials.
Ancient glass continues to inspire both makers and collectors, both for its exceptional beauty and its remarkable sense of historic importance. Click here to view our current collection of Roman glass.