The story of this place
A Roman harbour on the Oer-IJ
At the beginning of the first century, the area around Velsen looked very different. The Oer-IJ formed a broad waterway between the hinterland and the North Sea. Along its banks lay fertile ground where Frisian communities lived, kept livestock and cultivated fields.
For the Romans, this waterway was strategic. Ships could sail from the Rhine and Vecht river systems to the Oer-IJ. Around AD 14, a fortified military base was established here, now known as Velsen 1.
Water formed one boundary of the camp and was also essential to its function. Timber jetties, revetments and probable boathouses made Velsen 1 not only a fort but also a harbour complex where ships could dock, be maintained and supplied.
Archaeologists found weapons, shoes, tools, wooden objects and refuse. Together, these finds reveal how soldiers lived and worked here and organised traffic over the water.
Castellum Flevum and the Frisian revolt
Velsen 1 is usually associated with Castellum Flevum, the fort mentioned by the Roman writer Tacitus. Its location, date and traces of violence make Velsen the most likely candidate. The identification is widely accepted but not directly proven.
Relations between the Romans and the Frisians initially involved trade, diplomacy and military cooperation. This changed when the Romans demanded increasingly large cattle hides. For the Frisians, the tax became impossible to meet.
A revolt broke out in AD 28. The Roman occupation in the region was attacked, and heavy fighting also took place at Velsen. Burn marks, damaged weapons and human remains show how violent the confrontation was.
After the revolt, Velsen 1 was abandoned. The harbour fort disappeared, but traces of the attack remained exceptionally well preserved in the soil.
Velsen 2 and a greater Roman ambition
A second base was later built not far from Velsen 1. Velsen 2 was much larger and covered at least eleven hectares. The site offered space for a substantial military force.
Its construction points to plans for a large-scale military operation in the north. The camp may have served as a base for further campaigns along the coast and towards Frisian territory.
The precise function of Velsen 2 has not yet been fully established. Its size and layout make clear, however, that it was more than a small frontier fort. It was a large military camp with an important logistical role.
This base was also eventually abandoned. Roman military presence at this location then came to an end.
How the Roman landscape disappeared
After the Romans left, the landscape slowly changed. The Oer-IJ silted up and lost its importance as a broad waterway. New soil layers covered the remains of the forts and their harbours.
Much later, the North Sea Canal, industry, roads and tunnels transformed the area again. Modern construction projects formed both a threat and an opportunity. They disturbed parts of the archaeological record, but also revealed remains that would otherwise have stayed hidden.
Roman pottery came to light during work on a German anti-tank ditch. Later excavations revealed how extensive and exceptional the sites were.
What still lies beneath the ground today
Almost nothing of Velsen 1 and Velsen 2 can be seen above ground. The present surroundings are shaped by traffic, buildings and greenery. Yet beneath this modern landscape, parts of defences, buildings, harbours and refuse zones remain preserved.
The significance of Velsen lies precisely in this hidden scale. Two successive Roman bases stood here beside a vanished waterway. Here Romans and Frisians met, traded and eventually fought over the same coast. Beneath modern Velsen still lies the silent evidence of that Roman presence and the confrontation that followed.