Tjomp, tjomp, tjomp: graves near the dam where Rotterdam was founded in 1270

Tjomp, tjomp, tjomp: graves near the dam where Rotterdam was founded in 1270

A pewter plate, a hammer, a fucking dagger, several coins and a gold-colored piece of jewelry. In a bright green shack on the edge of a large construction site in the center of Rotterdam, right next to the Markthal, archaeologist Maaike Sier and field technician Gilbert Kempenaar look over objects found that morning. In the plastic bin next to it are muddy remains of medieval leather shoes. Sier: “You wouldn’t expect it, but those leather remains were used en masse to shore up the dike.”

Here, between the modern Markthal and the medieval Laurenskerk, construction of the luxury apartment complex RottaNova will start in June. Archaeologists from the Rotterdam Municipal Archeology Department still have time to dig through the muddy construction pit, which is more than six meters deep. In May, trenches will be used to look even more deeply at even older times.

River Rotte

Maaike Sier climbs out of the green shed and steps into the construction pit in high leather boots to show the major discovery that was already made during the preliminary investigation: a drainage sluice in the dam.

Not just any dam. This is the dam that gave Rotterdam its name, built around 1270 at the mouth of the Rotte river. It was the final part of the diking of the Rotte that started around 1200, to make the banks habitable. Kempenaar: “The Oude Dijk, now a street in Kralingen, was once also part of that regional dike system. That ran far inland.”

The closing dam built around 1270 had to protect the diked area against the tide that until then poured into the Rotte twice a day from the Nieuwe Maas, which was then still called Merwe. Kempenaar about the dam: “A large work: two and a half meters high, 500 meters long and 27 meters wide.”

The locks in the dam were built to drain the water from the Rotte at low tide – via a handy system of doors that closed automatically at high tide. Sier: “Small boats could therefore continue sailing at low tide.” Sier points to a map on the wall of the shack: “There were a total of nine locks in that dam. We have probably now found one of the oldest wooden locks, that of the Nauwe Kerkstraat. We have previously been able to date the dam itself, thanks to a wooden boat, a punt, that was found during the construction of the railway tunnel.”

Once the dam was in the Rotte, things went quickly. Around 1300, a few hundred people already lived on and around that large dam. First, wooden houses were built and the habitation formed a ribbon perpendicular to the Rotte, today the Hoogstraat, which now only has a small height difference with the surrounding area. Only forty years later, in 1340, the place already had a few thousand inhabitants and the residents of Rotterdam were able to purchase city rights from the Dutch count. Twenty years later, canals were dug and around 1500 Rotterdam had a stone city wall.

In the shadow of Schiedam

At this time, the craft and trading city of Rotterdam was still economically in the shadow of Schiedam (slightly earlier, founded in a similar way on a dam in the Schie) and the much older Dordrecht. The great boom began in the sixteenth century with renewed growth of the port city in the nineteenth century.

The original Rotterdammers on the dam were not even the first inhabitants of that place. From about 950 to 1050, farmers, fishermen and craftsmen also lived along the undiked Rotte in the settlement that was then called Rotta. They lived in farms made of wood and clay, with thatched roofs. It was a small village with a large network, with coins from Tiel and indications of trade with England.

The flooding was extensive. Excavations during the construction of the Markthal showed that the house yards in Rotta were repeatedly raised due to rewetting. Due to the drainage of the peat for agriculture, the soil sank and the mounds had to become higher and higher. In the twelfth century the last inhabitants left the swamp that had become the mouth of the Rotte.

Sucking mud

Maaike Sier leads the way into the construction site via a narrow metal staircase. Thump, thump, thump. With every step she pulls her boots out of the sucking mud. Everywhere there are archaeologists with yellow helmets, orange jackets and boots, carefully digging with shovels and then scraping away with trowels. The rough work is done with excavators. When a special find is made, quite often at this location, the joint archaeologist app group explodes with enthusiastic messages.

Archaeologists at work in the enormous construction pit in which RottaNova will be built, full of remains of ancient locks, quays and revetments.
Photo Archeology Rotterdam / David Rozing

Look, Sier shouts over the sound of an excavator. She points to a row of posts. It is part of a wooden revetment that was used to strengthen the harbor wall outside the dike. A row of neatly arranged planks rises from the mud. Parts of (then old) ships from the thirteenth or fourteenth century were often used for revetment, she says. “This is such a skin of a ship.” It is clearly visible that the planks are placed together crooked, a typical medieval shipbuilding style. Sier: “We will then bring in a maritime archaeologist. He looks at the type of wood, nails, handles, and can thus date and place them.”

Every time a high-rise building with an underground parking garage or bicycle shed is planned in Rotterdam, it is checked whether archaeological research is required. If the answer is ‘yes’, then Maaike Sier and her team from Archeology Rotterdam (a department of the municipality) will take action. Like now next to the Markthal and opposite the central library.

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They receive help from archaeologists from BAAC for this major project. BV and ADC-Archeoprojecten. It was already clear from previous research, including before the construction of the Markthal, that Rotterdam (the dam in the Rotte) originated there. This makes the area extra attractive and exciting for archaeological research.

Thump, thump, thump, Sier splashes further through the mud. Here, she says, is the Zevenhuizersluis. The lock is made of brick and finished with natural stone on the inside. “The larger the stones, the older,” says Sier. “And these are big! Nice huh?!”

The larger the stones, the older. And these are big! Nice huh?!Maaike Sier archaeologist

Earlier in the shed, Gilbert Kempenaar talked about the incredibly ingenious drainage system that the early Rotterdammers built in the area in the thirteenth century to keep their feet dry. With ditches, drainage canals and locks, which were checked at regular intervals. The Schieland Water Board was founded in 1273 to ensure that everything was well maintained. Kempenaar chuckles as he explains how some Rotterdammers were already evading the rules and opening the lock a little to have a better chance of catching good fish.

Inner rot

It is one of the last times that Rotterdam archaeologists can conduct excavations in the middle of the city. Because after the RottaNova, there are no major construction projects planned around the Binnenrotte. Kempenaar: “For that, some demolition first has to be done.”

In the right room of the green shed, a few builders from Dura Vermeer and JP van Eesteren are sitting happily watching the archaeological activity. Construction of the apartment complex has not yet started, but they have already constructed the steel sheet piling around the construction pit. And that crane that lifts away the large debris? “It’s ours too.”

The project developer’s chief executive turns back and forth on his office chair in his work clothes. “I now live in Zoetermeer,” he admits. “But don’t put that in the newspaper. I am entirely a Rotterdammer. Born in the South. He points to the archaeologists in the pit. “We really like this.”

Photo of excavation site with drawn reconstruction of the medieval harbor, just outside the dam. The houses in the foreground are on the dam in the Rotte.
Photo and reconstruction: Archeology Rotterdam.