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Advanced steel and iron production in Norrbotten already 2,000 years ago

Published: 17 February 2022

Archaeological excavations on Sweden's northeastern border with Finland show that hunter-gatherer cultures in northern Fennoscandia around 0 AD mastered advanced iron-making and steel-making techniques, knowledge that was previously belived to exist only in ancient Rome. The excavations have been made in Sangis, between Kalix and Tornio, and Vivungi about 150 km from Pajala.

Traditionally, iron handling has been linked to the agricultural community. Previous finds of iron and steel objects in hunter-gatherer cultures have been interpreted as imported goods. But we can prove that those who lived in these areas mastered techniques that were previously thought to be introduced to Sweden with the miners in the 17th century, says Kristina Söderholm, project manager and professor of technical history at Luleå University of Technology

During the excavations, iron-making furnaces have been found, so-called bloomery furnaces, with which malleable steel can be produced. Axes and knives made of several layers of steel and iron with different properties have also been found. The multilayer technology increases the tool's durability and cutting ability. One of the axes is one of the oldest examples of so-called heat-treated steel objects that have been found in northern Europe.

The top of an iceberg

Most likely the finds are just the tip of the iceberg; similar finds will probably be found throughout the northern Fennoscandian region. The new findings indicates that one must reconsider established notions of how these societies were organized and how knowledge about, among other things, metallurgy has spread around the world. This is shown by interdisciplinary research from Luleå University of Technology.

Previous finds from excavations preceeding the hydropower regulation in the region during the 1940s-80s will probably be reinterpreted. Due to a tenacious attitude that iron handling is a late phenomenon here in the north, these finds have long been ignored in archaeological research, says Carina Bennerhag, archaeologist at Norrbotten Museum and doctoral student in history at Luleå University of Technology who has Kristina Söderholm as supervisor.

Archaeometallurgists from Uppsala University have made chemical analyzes of the finds which show that the iron ore comes from lakes and bogs in the region. Consequently, these are not imported goods. Furthermore, the analyzes show that different types of ore have been used to produce iron with different qualities. For example, the hunter-gatherer culture in the area was well aware that iron ore with high levels of manganese provides a hard carbon steel that is well suited for cutting edges.

Iron production and steel production at this advanced level is a multi-stage process that requires the involvement of many people and specialist competence at each stage of production. For example, you need to know which type of clay is best suited for building furnaces that can withstand the high temperatures required for steel production, says Carina Bennerhag.

Large-scale advanced organization

The findings show that this is not a small-scale, impulsive activity but an extensive production of up to 80 kilos of iron from each kiln, which can be compared with estimates of the consumption of iron in a contemporary farm household of about five kilos per year. Iron and steel were thus no less important in the Fennoscandian hunter-gatherer cultures. The production required an advanced organization and periods of residence that has not previously been associated with the hunter-gatherer cultures.

The analyzes show that the products are not the result of experimentation,  which would have been the case if they had tried to copy another group's products. Consequently, the whole process has been mediated through apprenticeships with experienced metallurgists. The researchers believe that the metallurgical knowledge has been conveyed as different groups have converged at lakes with an abundance of fish. Furnaces similar to those in Sangis and Vivungi have been found in large parts of the northern Fennoscandian region. Traces of ceramics have also been found, which suggests that the lakes were nodes for the dissemination of knowledge in many different areas of technology.

Carina Bennerhag explains that iron research is strongly characterized by a center periphery - narrative when it comes to the spread of iron handlinit is taken for granted that iron handling istarted in a thought center in the south and from there was spread to the periphery in the north.

Findings further north that are older than those in the south have been ignored just because they do not fit into the usual picture. The spread is not an irreversible process sweeping across Europe from south to north. We believe that the inclusion of iron handling is an active choice and controlled by the networks you are part of. This means that you get a more irregular pattern of the spread. Iron handling in the north can thus be older or contemporary with that in the south.