The construction of the North/South line in Amsterdam is an unprecedented piece of technical ingenuity. Never before has a metro line been built under an old city so deep and on such soft peat soil. This also offered unprecedented opportunities for archaeological research.

Of course, the technique comes first. But in the wake of the engineers and the excavators came the archaeologists. They descended deep into the ground and explored strata from our century to 10,000 years ago. They have been busy for almost two decades from planning until now, the opening of the Rokin metro stop with the showcases full of archaeological finds. Jerzy Gawronski, urban archaeologist and professor of archeology at the University of Amsterdam, talks about it infectiously. He has led this archaeological monster project.

Building a metro is a standard job, but not in Amsterdam

With fifty men

The news often came that the construction of the metro tunnels did not run smoothly. Reality was a lot more unruly than the drawing board. This also had consequences for the archaeologists. “The archeology had to be integrated into the building process. Every day when I entered the construction site, my planning could be completely changed again. So we had to constantly improvise and adapt.”

Gawronski worked with a permanent team of fifteen people and around it another hundred extra archaeologists, experts, students and volunteers. The excavators were not stopped so that the archaeologists could quietly view and investigate everything. “We had little time and sometimes worked with as many as fifty people at a time to meet the schedule.”

You can tell Gawronski is proud of his team. They did everything themselves:first the excavations, then cleaning the finds, interpreting them, searching for historical information, restoring, filling the database, putting all the finds in plastic bags and storing them in the depot. “We even made the 85 panels with 10,000 objects on them for the showcases at the Rokin metro stop. These fifteen people have now grown into specialists, while some were unemployed when they started this.”

Under the river

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When excavating the stations, the archaeologists were presented with an unprecedented cross-section of the Amsterdam soil, dating back to the Holocene, 10,000 years ago. The metro line runs from Amsterdam North to the Zuidas, but from an archaeological point of view, the construction sites at Damrak and Rokin were the most interesting. Not only is it the oldest part of the city, but the metro line also follows the flow of the river De Amstel, a natural water channel. This is to avoid buildings in the city as much as possible and to prevent subsidence.

The Amstel was only filled in at the Rokin in 1937 and contains traces of the earliest habitation from the twelfth century. Over the centuries, the Amstel has been dredged to give ships enough depth, but no further than three meters was necessary. “The bottom of De Amstel turned out to be twelve meters deep and the peat soil was soft, where things could easily sink into.” This has happened frequently. Of the nearly 700,000 archaeological finds, most come from this area.

A lot of shipping

Before the Central Station was built at the end of the nineteenth century, De Amstel opened onto the IJ. The city's harbor was located here, where the two banks of De Amstel were connected by the Nieuwe Brug. “Various activities took place on and around the bridge. It was the harbor entrance and part of the city defense until 1600, where trade, games and fights took place. For example, young people from the Oudezijds and Nieuwezijds neighborhoods gathered on the bridge to play mats and their weapons often end up in the water.”

The archaeologists found many artifacts related to shipping, such as the frequently broken ship hooks used to maneuver sailboats in a busy harbor. Finds that are silent proof of life and work on the banks have also been frequently found. People lost property or illegally used the water as a waste pit. This was difficult to counter, as evidenced by the many city ordinances on dumping waste.

New genesis

All these recovered traces tell the story and provide insight into the material culture of the city. This was to be expected and they confirmed the already existing image of Amsterdam as a busy trading network. What was surprising were the finds from the deepest layers of the earth, which they would never have discovered without this project. They are rewriting the earliest history of the area.

“The oldest finds are from 2400 BC. and consist of tools of stone and bone and shards of pottery. On the location of the current Maison de Bonneterie on the Rokin was a farm belonging to a family who lived there during certain seasons. This habitation has not been demonstrated before, this is really new knowledge. The findings show that this was not an incident. Seasonal habitation continued until the twelfth century.” Until that time, the Amstel estuary was wet and swampy and could not be inhabited all season, unlike the surrounding area.

Floods in the twelfth century changed the landscape. The Amstel estuary widened and the IJ became an arm of the Zuiderzee (now IJsselmeer). The perfect place for shipping connections to the North Sea and beyond. “Within a few years after the great flood of 1170, residents from the area formed a village in this new place. From the outset it was a center of merchants and craftsmen, which is the essence of Amsterdam. There are plenty of older cities in the Netherlands but Amsterdam beat everyone. Back then it was already a city of young dogs”, says Gawronski.

For the public

The river Amstel plays the leading role in this archaeological project, not the depth of the excavations or the massiveness and complexity of the finds, however exceptional those aspects may be. Construction sites are generally located on land, in the city. Now there was the opportunity to examine the river bed and the submerged remains. “Waterways have their own research dynamics and you don't often get the chance to spoon out a river. I think the best thing is that we were able to give De Amstel a voice.”

The finds will not disappear under lock and key, but will remain accessible to the public and researchers. Everything is listed in a publicly accessible database, there is the paper catalog Spul and the website Below the surface Amsterdam and showcases with a selection of the finds. “The idea behind this was to do something with that crazy mass of finds, to show them to Amsterdammers and visitors. And that had to be at the Rokin because this is the only stop in the heart of the city.”

The objects are arranged by theme, but there is no text or context in the display cases. Interested parties can find explanations about the themes on the website. It also contains short stories behind featured objects, which are still being completed by the archaeologists. Interactive is making your own online display case, with objects from the database. “Within three weeks people had already made more than 1500 showcases. And this enthusiasm does not only come from the city, no, the whole world is participating. Spain, Russia, China, South America, you name it. People are realizing how special it is that so much cultural information has been made public and accessible.”