Researchers analyzing ancient metalworking debris from a Kushite temple in Sudan have uncovered evidence of localized bronze production and uniquely decorated manufacturing tools from the Meroitic period. The findings reveal the diverse copper exchange networks connecting ancient Nubia to the wider Mediterranean world while demonstrating the skilled application of multiple heating techniques in ancient African foundries. The report was published in the journal Archaeological and Anthropological Sciences.
The Meroitic phase of the Kushite empire flourished between the third century BCE and the third century CE along the Nile River in what is now Sudan. This era represents a period of significant political and cultural influence in northeast Africa. The people of Meroitic Nubia inhabited the Berber-Abidiya region, building urban centers like Dangeil on the eastern bank of the Nile just south of the river’s fifth cataract.
The city of Dangeil featured a prominent temple dedicated to the god Amun and was surrounded by a semiarid landscape that necessitated well-managed trade routes to access distant raw materials. Archaeologists have previously documented the architectural achievements of the Kushite civilization, yet the daily technological practices of its craftspeople remain largely unexplored. Specific details regarding how Nubian artisans melted and alloyed metals during this era represent a major gap in the historical record.
Only one other study has investigated secondary metallurgical processes, which involve the melting and mixing of existing metals rather than extracting them from raw ore, within ancient Nubia. Understanding these manufacturing steps offers direct insight into the technological sophistication, regional trade partnerships, and material economy of the Kushite state.
The investigation was led by Frederik W. Rademakers, affiliated with the British Museum and KU Leuven, alongside Aude Mongiatti and Julie Anderson from the British Museum. The team scrutinized an assemblage of production waste excavated from a large pit dug during the construction phase of the Amun temple at Dangeil. The deposit contained 35 crucible fragments, 15 casting mold fragments, two pieces of air-blowing clay tubes called tuyères, and a fragment of a blowpipe. These materials date to between the mid-fourth and early second century BCE based on radiocarbon analysis of associated charcoal.
To interpret the metallurgical activities, the researchers first screened all crucibles and molds using a scanning X-ray fluorescence device. This non-destructive technology bombards the ceramic surfaces with X-rays to detect the unique energy signatures of metal contamination, helping scientists identify which pots held molten metal without altering the artifacts themselves. Following this survey, the researchers cut cross-section samples from 21 crucible pieces, seven molds, and three miscellaneous technical ceramics.
These samples were processed into polished blocks and placed under a scanning electron microscope equipped with an energy dispersive spectroscopy system. This setup allows scientists to view microscopic structures and measure the precise chemical makeup of the ceramic fabric, the external heat-glaze, and the internal melted residues left by the metal charge. Additionally, the team extracted trace metals from the artifacts, specifically three small metal spheres called prills trapped in the crucibles, alongside two fragments of thin-walled vessels.
These five metal samples underwent acid digestion for trace element and lead isotopic analysis. Lead isotopic analysis functions by measuring the unique ratios of lead variants in a piece of metal. These ratios can often be matched to specific geographic geological deposits where the ore was originally mined.
The physical evidence indicates that the Dangeil artisans actively produced tin bronze, an alloy made by melting copper and mixing in tin to create a harder, more durable material. The chemical residues in the crucible samples show that these craftspeople were alloying fresh tin into the copper while also recycling existing copper alloys. Traces of lead were identified in the internal crucible residues, but the levels suggest the lead was already present in the copper sources rather than being intentionally added during this specific melting phase.
The structural features of the ceramics demonstrate a high degree of specialization among the artisans. The casting molds were composed of a sandy, friable fabric that withstood the extreme heat of molten metal but could easily be broken away once the cast object cooled. The shapes of the molds point to the production of objects with rough outlines, possibly building tools like chisels that required subsequent hammering to achieve their final form.
The simultaneous discovery of a blowpipe and a tuyère, which is a clay nozzle connected to a mechanical bellow, shows that the metalworkers utilized multiple methods to superheat their hearths. Bellows likely provided the primary draft to blow large volumes of oxygen into the fire to rapidly raise temperatures, while the smaller blowpipes offered localized air flow that the artisans could direct by breath to complete smaller melting or casting tasks.
The design of the crucibles themselves presents a highly unusual characteristic for the ancient world. The rims of many crucible fragments were deliberately shaped by hand into wavy, scalloped, or saw-tooth patterns. In most ancient societies, technical ceramics used in high-temperature crafts were strictly functional tools built only to withstand extreme thermal stress. The structural additions of scallops and waves offer no mechanical or thermal advantage for melting copper. The presence of non-utilitarian decoration on these industrial vessels suggests that the Dangeil craftspeople possessed a distinct sense of identity and personal expression in their trade.
Additionally, the lead isotopic signatures of the five metal samples connect the Dangeil artisans to expansive trade networks. The signatures of the metal prills closely match those of objects from other Meroitic sites like Kerma and earlier Egyptian settlements. This pattern points to shared provisioning networks that supplied raw materials or scrap metal to both Nubia and Egypt, potentially pulling from shared eastern Mediterranean or Sinai ore sources.
Interpreting the Dangeil metalworking debris presents several challenges related to preservation and sample size. The extreme fragmentation of the casting molds makes it impossible to determine the precise types of objects the artisans were producing. While the molds suggest the creation of tools, archaeologists cannot verify if these implements were intended specifically for the construction of the Amun temple or for wider public use.
The isotopic analysis relies on an exceptionally small dataset of only five metal samples. This limited sample size prevents the researchers from confirming the specific geological origins of the copper or reconstructing the full scope of the Meroitic trade routes. The chemical signatures supply evidence of broad exchange networks, but pinpointing the exact mines requires a much larger database of comparative Meroitic copper alloys.
Future research paths involve expanding the chemical and isotopic catalog of Kushite metalwork. Analyzing a greater volume of finished Meroitic bronze objects could clarify whether artisans intentionally selected specific alloys, such as leaded versus unleaded bronze, for distinct types of tools or luxury goods. Comparing broader samples from across Sudan and Egypt may eventually reveal the complete lifecycle of ancient Nubian metals, from their initial extraction to their final casting in the foundries of Dangeil.
The paper, “Crucible technology at Dangeil. New insights into Kushite copper alloy metallurgy,” was authored by Frederik W. Rademakers, Aude Mongiatti, and Julie Anderson.