The Iron Streets of Pompeii and the Curious Case of Liquid Roman Iron


One of the great joys and frustrations of academia is coming up against a phenomenon that defies explanation. In 5CollDH undergraduate fellow Juliana van Roggen’s case, it’s asking why there are small iron deposits scattered around the ancient Roman city of Pompeii. In collaboration with an ongoing archaeological project, she’s creating a public, digital resource that maps the city in new and unusual ways. In her own words:

Unlike my colleagues, my project does not focus on creation. Instead, I am tackling a rather unusual archaeological research question. Over the summer of 2014, I examined molten iron distributed in the streets of Pompeii and collected data and GPS locations. This question explores why the Pompeians utilized a relatively expensive material to mend their pavement stones and how the Pompeians were able to melt iron and transport it along the vast network of streets.

Although most of my recent energy has been put into analyzing the data, a big chunk of my work is also on making all of the archaeological material presentable to the general public. With the use of Esri Story Maps, I am exploring ways to make distributional data accessible and easy to understand to the average viewer. I am finding Story Maps’ user interface to be incredibly intuitive and easy to use unlike some of the other programs I had explored and I can’t wait to actually get to work with the program in full. Before I can create the online map, however, my data needs to be cleaned up. This process is taking significantly longer than I thought, as I have almost 440 data points to work with.

One of the things that has significantly kept me fascinated with this research is the question of how. How did the Pompeians do it? It is commonly assumed by scholars and archaeologists that the Romans did not have the technology to produce liquid iron. While they had the ability to extract iron from slag, the process did not create iron in liquid form. Bloomeries would create a “spongey” iron chunk that could then be hammered into shape. The ability to melt iron was not present in Europe until the middle ages. It is clear, however, that the iron was poured into the pavement stones at Pompeii. On one hand, this adds a level of intrigue and opens connections to other areas of study. No other time have I had the chance to study trading patterns in the Mediterranean in such a deep level or learned about ancient smelting practices. On the other hand, it is incredibly frustrating. It is like we know what the puzzle should look like when completed and we have some of the pieces but none of them fit together into that beautiful image. We are clearly missing pieces before we can have a cohesive narrative.

I’ve been consulting an old smithing and archaeology friend of mine who taught me to smith my first knife and taught me the workings of a forge a few years ago. He specializes in blade smithing among other skills (he is an expert flint knapper as well, which is significantly harder than it seems). Although he has little casting experience, he is fairly well versed in the practice theoretically. We have been tossing ideas back and forth about the ways the iron could have been melted and transported with the technology available to the Romans. He is absolutely fascinated by the question of how they transported molten hot liquid iron. Although we have no way in which to practice melting iron, we may play around with his forge a bit if we both have free time. I am quite eager to return to a forge after so long.

Juliana van Roggen
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Juliana is one of six 5CollDH undergraduate fellows for the 2014-2015 academic year.