Galilee Glass Kilns Prove Ancient Israel’s Manufacturing Prowess

Site is thought to be a center for making 'Judean glass,' known and sold throughout the Roman Empire.

Chunks of glass that were found in the ancient factory in the Galilee.
Israel Antiquities Authority

Four 1,600-year-old glass kilns discovered in a rescue dig in the Galilee prove that ancient Israel was a world center of glass production in antiquity. The products of these kilns, the oldest ever found in Israel, were sold throughout the Roman Empire.

The kilns are considered an archaeological find of international importance. Located between the Ha’amakim and Yagur junctions, they were uncovered during work on a new rail line for the Jezreel Valley.

According to Yael Gorin-Rosen, the head curator of the Israel Antiquities Authority’s glass department, each of the four kilns was capable of producing at least 10 tons of raw glass in a single manufacturing process that took between one and two weeks. “This is the oldest factory discovered in Israel, and it was built with the best technology,” she said. “According to written sources, we knew there was glass made in the region, but we didn’t find the kilns until now.”

The glass factory was discovered by accident last summer, during an excavation prior to work on the rail line. The head of the dig, Abdel Al-Salam Sa‘id, noticed chunks of glass, a floor and a layer of ash inside a trench. “We exposed the remains of floors, vitrified brick fragments from the walls and the ceilings of the kilns and clean raw glass chips,” said Sa’id. “The excitement that gripped us when we understood the importance of the findings was extremely great.”

The kilns had two chambers, a firebox where the kindling was burned to very high temperatures, and a chamber in which the raw materials for the glass (beach sand and salt) were melted together at temperatures of around 1,200 degrees Celsius until huge chunks of raw glass were formed.

According to Gorin-Rosen, the salt was imported from Egypt. At the end of the process the kilns were cooled and the large blocks of glass were broken into smaller chunks and sold to workshops where they were remelted into vessels.

In ancient Rome, the use of glass began to spread because of its transparency and beauty, and because delicate vessels could be produced relatively quickly by glassblowing, which was introduced during that era and substantially reduced the cost of the products. From Roman times glass was used in private homes and in public buildings for windows, mosaics and light fixtures. As demand increased, factories that could produce very large quantities of glass, like the one discovered in the north, were established.

According to a price edict issued by the Roman Emperor Diocletian in 301 C.E., there were two kinds of glass: The first was known as Judean glass (from the Land of Israel) and the second was Alexandrian glass (from Alexandria, Egypt). Judean glass was light green and less expensive than Egyptian glass.

Until now, however, the location of the facilities that manufactured this Judean glass, which was a branded and price-controlled product known throughout the Roman Empire, was unknown. The current discovery provides the missing link in the research. Since the glass was discovered, researchers from all over the world have come to examine the kilns, and in a few months the discovery will be displayed to the public at the Carmel Zevulun Regional High School.