Lugdunum Batavorum

The Brittenburg (Classical Latin: Batavorum Lugdunum) is a Roman ruin west of Leiden, presumedly of the even older Celtic Lugdunum fortress, that was visible on the beach between Katwijk aan Zee and Noordwijk aan Zee after storms in the years of 1520, 1552 and 1562. It was originally a large complex located at the mouth of the Oude Rijn (old river Rhine), which today is believed to be about a kilometer westwards (offshore in the North Sea) of the current location of the European Space Research and Technology Centre.

The word dunum, traceable in Gaelic place names in the present day (Dundalk, Dunrobin Castle) and meaning "fortress" or "castle", is a typically Celtic element in European place-names.The site, known as "Brittenburg", was still visible in the dunes in the fourteenth century, but the gradual advance of the sea made the ruins lie on the beach in the sixteenth and seventeenth century. Today, they must be somewhere in the Rhine estuary, inaccessible for archaeological research. All that remains is a small set of finds, taken away in the sixteenth and seventeenth century, and a famous map by Ortelius. A copy of the old Roman map Tabula Peutingeriana shows Brittenburg as Lugduno on the coast with two towers. Eastwards from that point, two roads run towards Noviomagi (Nijmegen). Along the northern route, the following towns can be seen: Pretorium Agrippine (Valkenburg (South Holland)), Matilone (Leiden), Albanianis (Alphen aan den Rijn), Nigropullo (Zwammerdam), and Lauri (Woerden). All of these locations are situated on the Oude Rijn. The southern route begins with the town Forum Hadriani (Voorburg), shown directly south of Matilone. These towns were connected by the Fossa Corbulonis or Corbulo-canal.

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