TEHRAN - An interdisciplinary research team has successfully reconstructed a medieval iron smelting and casting complex at the Old Masuleh historical site in northern Iran, revealing advanced metallurgical expertise in the region.

Led by Farzad Asadi, a faculty member of Azad University, the project involved the experimental reconstruction of a four-stage furnace system documented through two decades of archaeological work. “This was not merely an architectural model,” Asadi emphasized. “Through experimental archaeology, we evaluated the operational dynamics, including airflow, thermal efficiency, and the complete process from sponge iron to cast iron.”

The findings demonstrate a highly developed technical system, featuring preheated air channels, permanent stone structures, and a dedicated casting setup. This distinguishes the Masuleh complex from simpler, temporary bloomery furnaces. Laboratory analysis of slag and iron produced in the experiment confirmed high material purity and control, supporting the theory that Old Masuleh was a permanent Iron production center.

Mustafa Pourali, director of the Masuleh World Heritage nomination dossier, stated this second, more detailed reconstruction phase revealed clear technological links to broader “Iranian-type” furnaces. The results, to be published internationally, underscore Old Masuleh’s role as a hub of technological exchange along historic trade routes like the Silk Road, connecting Iran with the Caucasus and Central Asia.

This resaerch adds a profound industrial dimension to the rich tapestry of Masouleh's cultural landscape. Masouleh is not only celebrated for its unique terraced architecture and harmonious adaptation to the forested mountains of Gilan, but also as a living repository of centuries of indigenous knowledge. The reconstruction of this advanced ironworking technology vividly illustrates that the historical significance of Masouleh extends beyond its visual charm; it was a center of innovation and skilled craftsmanship. Preserving and understanding this integrated landscape—where natural beauty, architectural genius, and industrial heritage converge—is essential for fully appreciating Iran’s civilizational legacy and strengthening the case for its global recognition.

AM