Lugdunum: Roman naval base and fortified military granary at the estuary of the river Rhine, modern Katwijk in the Netherlands
Finally, as if resolved to make war in earnest, he drew up a line of battle on the shore of the ocean, placed his ballistas and other artillery, and, no one knowing or able to imagine what he was going to do, he all of a sudden commanded they gather sea shells and fill their helmets and pockets with them [...]. As a monument of this victory, he erected a lofty tower, from which lights were to shine at night to guide the course of ships, as from the lighthouse of Alexandria.note[Suetonius, Life of Caligula 46; tr. J. Gavorse.]
This farce must have taken place on the beach near modern Katwijk, because we know for certain that Caligula was present in 40. In the preceding winter, a military base was constructed at nearby Valkenburg. It was called Praetorium Agrippinae; the first element of this name means "headquarters", the second is a reference to the emperor's mother Agrippina. The presence of the emperor at the mouth of the Rhine is certain, because a barrel has been found that once contained wine from the emperor's personal vineyards. As late as the sixteenth century, fishermen from Katwijk called a group of underwater ruins "the tower of Kalla". Because there has been continuous human occupation at the mouth of the Rhine, it is tempting to think that the site of the lighthouse was still been remembered.Apart from these stories, Lugdunum is only known to us from drawings from the sixteenth and seventeenth century, when the ruins of the ancient settlement (not the lighthouse) became visible on the beach. The precise location of the Brittenburg, however, is still hotly debated.
The drawing by Abraham Ortelius, one of the most famous cartographers of all ages, shows a building that can probably be identified with a horreum or military granary. The heavy walls with round towers suggest a date in the fourth century.
The ruins of the Brittenburg were probably sighted for the last time in the last days of October (or the first days of November) 1954. Unfortunately, nobody has recorded their precise location. Modern archaeologists have been unable to trace the ruins of the 'Brittenburg', which have become one of the most famous and romantic mysteries of Dutch archaeology. The violence of the sea has probably destroyed the remains of the castle beyond recovery.
The Renaissance expression "Lugdunum Batavorum" to describe the nearby town of Leiden is erroneous. In Antiquity, Leiden was called Matilo.
- D. Parleviet, "De Brittenburg voorgoed verloren" in Westerheem 51/3 (2002)
- Simon Wynia, "Gaius was here. The Emperor Gaius' Preparations for the Invasion of Britannia: New Evidence" in: H. Sarfatij, W.J.H. Verwers, P.J. Woltering (eds.), In Discussion with the Past. Archaeological studies presented to W.A. van Es (1999 Amersfoort)