A new article published in Archaeometry has uncovered the first direct evidence of deliberate arsenical bronze production in ancient Egypt, demonstrating that Middle Kingdom metalworkers were much more technologically advanced than previously believed.

The background shows an aerial orthopH๏τograph of the southern part of Elephantine Island with the Realities of life excavation squares highlighted in blue, south-east of the Dynasty 3 granite pyramid. Credit: Drawing: Peter Kopp. © German Archaeological Insтιтute, Cairo Department / Kmošek, J., & Odler, M., Archaeometry (2025)

The discovery, which was made on Elephantine Island near Aswan, dates to around 2000–1650 BCE. The researchers identified “speiss,” a metalworking by-product containing high levels of arsenic, iron, and lead, which was used deliberately as a reagent for arsenical bronze manufacturing. This is the earliest documented example of controlled alloying with arsenic in Egyptian metallurgy.

For a long time, scientists ᴀssumed that ancient Egyptian arsenical copper was the result of natural contamination in copper ore. However, the new findings reveal that Middle Kingdom metalworkers deliberately manipulated the chemical composition of their metals. By adding speiss to molten copper, they enhanced the hardness and durability of bronze—qualities required for tools, weapons, and ritual objects.

The research team, led by Ing. Jiří Kmošek of the Academy of Fine Arts Vienna and the Czech Academy of Sciences, and Dr. Martin Odler of Newcastle University, analyzed metallurgical debris from the Elephantine settlement area. The study was carried out in collaboration with the German Archaeological Insтιтute’s Cairo Department, the Insтιтut français d’archéologie orientale, and the Desert Research Center in Cairo, under the approval of Egypt’s Ministry of Tourism and Antiquities.

Selection of the fragments from the Middle Kingdom metalworking remains. Credit: Martin Odler, German Archaeological Insтιтute, Cairo Department / Kmošek, J., & Odler, M., Archaeometry (2025)

Through the integration of advanced compositional and microstructural analyses, including portable X-ray fluorescence (pXRF), optical microscopy, and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), the researchers identified fragments of speiss of metallurgical origin dating back to Egypt’s 12th Dynasty (19th century BCE). The remains came from House 175, which confirms that copper was alloyed with arsenic in ceramic crucibles through a controlled cementation process.

The study depicts various stages in the ancient production process that indicate that the speiss not only introduced arsenic but also trace amounts of antimony and lead into the final metal. These added elements likely affected both the physical composition of the bronze and the isotopic composition utilized by modern researchers in tracing the origin of the metal, complicating provenance studies.

Although the origin of the speiss is unknown, researchers are convinced that it was acquired from arsenopyrite ores in Egypt’s Eastern Desert. This implies access to specialized resources and possibly trade connections with regional or local communities that mined and processed materials of this type.

The discovery reveals a society already sophisticated enough to refine metallurgical techniques nearly 4,000 years ago—well before such techniques became widespread elsewhere. Interestingly, the controlled use of speiss demonstrates not only advanced scientific knowledge but also an advanced understanding of resource procurement and material transformation.

This find opens the door to further investigation into how ancient craftsmen acquired and exchanged metallurgical knowledge across Egypt and beyond the Near East.

More information: Kmošek, J., & Odler, M. (2025). Production of arsenical bronze using speiss on the Elephantine Island (Aswan, Egypt) during the Middle Kingdom (Middle Bronze Age) (c.2000–1650 BCE). Archaeometry, (arcm.70008). doi:10.1111/arcm.70008