A recent scientific analysis of pottery fragments from the ancient city of Cumae in Southern Italy has shed new light on Roman trade networks during the 2nd to 4th centuries CE. Published in the Journal of Archaeological Science: Reports, the study examines nineteen transport vessels, known as amphorae, to trace their origins back to North Africa. By determining the chemical and mineral composition of these jars, researchers have provided new evidence regarding the commercial relationships that sustained the Roman Empire’s economy.
Cumae holds the distinction of being the first Greek colony founded on the Italian mainland, located just west of modern Naples. By the Roman period, the city had evolved into a significant hub within the Campania region, an area historically celebrated for its fertile volcanic soil and busy ports. The local Forum served as the heart of political and economic life where merchants and citizens gathered to exchange news and commodities.
During the early Roman Empire, Italy dominated the production and export of goods like wine and olive oil across the Mediterranean. However, a significant economic shift occurred between the 2nd and 4th centuries CE. Provinces in North Africa began to outpace Italian producers, flooding the market with their own agricultural products transported in large ceramic vessels.
Archaeologists have long worked to map these changing trade routes to understand how provincial goods replaced local ones in daily Roman life. The transition from a Rome-centered export system to one where the capital imported vast amounts of resources from its provinces marks a pivotal moment in history. The physical traces of this trade are best preserved in the millions of amphorae shards left behind.
These ceramic containers were the shipping crates of the ancient world, designed to hold olive oil, wine, and fish sauce. While historical texts mention these trades, the physical evidence offers a more granular view of exactly which regions were supplying which cities. The excavation of the Forum at Cumae has produced a large volume of these fragments, prompting questions about the specific origins of the goods consumed by its inhabitants.
To trace the specific origins of these imported goods, a team of researchers selected nineteen amphora samples excavated from the Roman Forum. The shards were chosen based on their shape and surface features, which visually resembled known North African styles. The team employed a combination of geological and chemical techniques to analyze the clay paste used to make the vessels.
One primary method involved polarized light microscopy, where thin slices of the pottery are examined under light to identify mineral inclusions and fossils. This allows scientists to see the “recipe” of the clay, including the specific types of sand and rock fragments present. The team also used X-ray fluorescence to determine the chemical bulk of the samples, measuring the concentrations of elements like calcium and iron.
To understand how the pots were made, the researchers used X-ray powder diffraction and scanning electron microscopy. These high-tech methods revealed the mineral changes that happen during firing. By looking at the microscopic structure of the ceramic, the team could estimate the temperatures inside the ancient kilns.
The investigation focused on distinguishing between different geological signatures found in North Africa. The region is geologically diverse, with distinct differences between the sedimentary basins of Tunisia and the metamorphic rocks found in parts of Algeria. By matching the minerals in the pottery to these geological maps, the team aimed to pinpoint the specific workshops, or ateliers, where the pots were thrown.
The physical analysis confirmed that the amphorae originated from several distinct regions along the North African coast. The mineral composition of the clay matched geological features found in modern-day Tunisia, Libya, and Algeria. Specifically, the presence of certain microfossils and quartz grains allowed the researchers to link the vessels to known production centers.
One group of samples contained rounded quartz grains and fossils typical of the Byzacena region in central Tunisia. These shards were linked to major production centers like Leptiminus and Salakta. These sites were industrial-scale producers known for exporting olive oil and fish sauces.
Another group of fragments displayed different characteristics, containing angular quartz and sandstone. These features align with the geology of the Zeugitania region in northern Tunisia. The study connects these vessels to workshops near Nabeul, a coastal town that remains famous for its pottery production today.
A smaller number of samples pointed to origins further afield. Some vessels appeared to come from Tripolitania, near the ancient city of Leptis Magna in modern Libya. One specific sample contained traces of metamorphic rock and brown mica, signatures that suggest it originated from the coast of Algeria, historically known as Mauretania Caesarensis.
These findings suggest that Cumae maintained extensive commercial connections with the African provinces even as the city’s local influence evolved. The variety of amphora types indicates that the city imported a wide range of goods. This points to a reliance on long-distance maritime trade to supply the population with dietary staples.
Technologically, the study revealed that North African potters possessed advanced knowledge of kiln operations. The vessels were fired at high temperatures, ranging from 850 to 1050 degrees Celsius. This intense heat created a durable ceramic body capable of withstanding the shocks of sea voyages and rough handling during transport.
The researchers also observed a “lightening” effect on the surface of the amphorae, where the outer layer appeared yellow or creamy gray. This characteristic likely resulted from using salt-rich water or clay with high calcium content. The chemical reaction during firing created a light-colored skin on the reddish clay, a trademark of African pottery that was likely an intentional result of their manufacturing process.
Some samples exhibited a “black core,” a dark grey strip sandwiched between red outer layers. This pattern indicates specific conditions within the kiln. It suggests that the organic matter in the clay did not fully oxidize, perhaps due to a rapid firing cycle or a reduction in oxygen supply during the process.
While the study successfully identified the general origins of the pottery, the sample size was limited to nineteen fragments. This small number provides a snapshot of the trade but may not represent the full volume or variety of goods entering Cumae. The researchers note that chemical data alone was not enough to pinpoint exact workshops without the supporting geological evidence.
A significant challenge remains the lack of comprehensive reference data for raw clay sources in North Africa. Many potential production sites have not been geologically sampled, making it difficult to match archaeological finds with specific clay pits. Future research aims to analyze a larger set of amphorae and collect more geological data to refine these provenance maps.
The study, “Provenance and first technological insights of African amphorae from the Roman Forum of Cumae, Southern Italy,” was authored by Michela Scanu, Filippo Barattolo, Carmela Capaldi, Antonella Ciotola, Francesco D’Uva, Vincenzo Morra, Maria Verde, and Alberto De Bonis.