What is left of the oldest kilns in the country, including the rare raw Judean glass they produced, was recently discovered by archeologists from the Antiquities Authority as part of the Jezreel Valley Railway Project in Mount Carmel, near Haifa.
The 1,600-year-old kilns, dating to the Late Roman period, indicate that Israel was one of the foremost centers for glass production in the ancient world, the authority said in a statement on Monday.
According to the authority, glass production kilns that date to the 6th or early 7th century CE were previously found at Apollonia in Herzliya, and came 200 years later than the latest discovery.
“The largest glass production facility from antiquity that has been found so far was exposed in the Beit Eliezer neighborhood in Hadera, where it was dated to the 7th-8th centuries CE, and the latest evidence we have of glass production in the country was revealed at Beit She’arim (next to Khirbat ‘Asafna), dated to the late 8th and early 9th centuries CE,” the Antiquities Authority said.
The recently discovered kilns are the earliest to be discovered so far in Israel, the authority said.
“Their relatively good state of preservation will make it possible to better understand the production process,” it added. “Researchers now hope that by means of its chemical composition, they will be able to trace the export of the glass throughout the Roman Empire.”
Indeed, Yael Gorin-Rosen, head curator of the authority’s Glass Department, said the discovery has far-reaching implications regarding the history of the glass industry, both in Israel and in the entire ancient world.
“We know from historical sources dating to the Roman period that the Valley of ‘Akko was renowned for the excellent quality of sand located there, which was highly suitable for the manufacture of glass,” said Gorin-Rosen.
“Chemical analyses conducted on glass vessels from this period, which were discovered until now at sites in Europe and in shipwrecks in the Mediterranean basin, have shown that the source of the glass is from our region.”
“Now, for the first time, the kilns have been found where the raw material was manufactured that was used to produce this glassware,” she continued.
Gorin-Rosen added that the excavation of the kilns has generated great excitement in recent weeks among glass researchers throughout the world, some of whom have traveled to Israel to see the discovery first hand.
Prof. Ian Freestone of University College London, who specializes in identifying the chemical composition of glass, deemed the find a “sensational discovery of great significance for understanding the entire system of the glass trade in antiquity.”
“This is evidence that Israel constituted a production center on an international scale; hence its glassware was widely distributed throughout the Mediterranean and Europe,” said Freestone.
The authority said the ancient site was initially discovered by chance last summer by archeologist Abdel Al-Salam Sa’id while he was overseeing infrastructure work being conducted on the new railway line from Haifa to the East.
“He suddenly observed chunks of glass, a floor and an ash layer inside a trench,” the authority said. “He halted construction work at the site and began preparations for an archeological excavation, the important results of which are now evident.”
In short order, Sa’id said he and his team exposed fragments of the floors, pieces of vitrified bricks from the walls, the ceiling of the kilns, and clean light green raw glass chips.
“We were absolutely overwhelmed with excitement when we understood the great significance of the finds,” he said. “The kilns that were revealed consisted of two built compartments: a firebox where kindling was burnt to create a very high temperature, and a melting chamber, in which the raw materials for the glass (clean beach sand and salt) were inserted and melted together at a temperature of c. 1,200 C degrees,” Sa’id explained.
“The glass was thus heated for a week or two, until enormous chunks of raw glass were produced, some of which weighed in excess of 10 tons. At the end of the manufacturing process the kilns were cooled and the large glass chunks that were manufactured were broken into smaller pieces and sold to workshops, where they were melted again in order to produce glassware.”
During the Early Roman period, the use of glass greatly expanded due to its favorable characteristics, including transparency, beauty, and speed with which it could be produced by blowing, an inexpensive technique adopted at the time that lowered production costs.
According to historians, glass was used in almost every household from the Roman Period onward, and was also utilized in the construction of public buildings in the form of windows, mosaics and lighting fixtures.
“Consequently, large quantities of raw glass were required, which were prepared on an industrial scale in specialized centers,” the authority said. “The installation that was discovered in the excavation is an example of one of these ancient production facilities.”
A price edict circulated by the Roman Emperor Diocletian in the early 4th century CE states that there were two kinds of glass: The first was known as Judaean glass, from Israel, and the second was known as Alexandrian glass, from Alexandria, Egypt.
Judaean glass was a light green color, and less expensive than Egyptian glass, the authority said.
“The question was: Where were the centers that manufactured this Judean glass that was a branded product known throughout the Roman Empire, and whose price was engraved on stone tablets so as to ensure fair trade?” the Antiquities Authority said.
“The current discovery completes the missing link in the research, and indicates the location where the famous Judean glass was produced.”
In a few months, the authority said, the public will be able to see the kilns and glass during an exhibition planned for Carmel Zevulun Regional High School, in the Zevulun region.