At the beginning of the Christian era the Romans live in the Middle Rhine region. For almost 500 years the northern frontier of their empire traverses this area. The Roman era is to have a strong influence on the region’s history and culture for many centuries to follow. Numerous finds confirm that there is also a Roman fortification in what is now Niederlahnstein, which takes advantage of the favourable location at the mouth of the River Lahn.
The Limes, the border fortification of the Roman Empire, runs through Lahnstein territory just 12 km east of the Rhine. It seals off the Empire against the Germanic tribes.
In the year 369 AD, after the Limes is abandoned, the Roman emperor of the time, Valentinian I, has a fortification and a boat landing stage built to secure the Rhine border. These are situated at a favourable strategic location on an island at the mouth of the River Lahn, surrounded by the arms of the estuary.
The fortification or Burgus is probably a three-storied tower with a floor area of about 20 metres by 13 metres and surrounded at a few metres’ distance by a deep trench. This solid stone tower with walls up to 3 m thick is known in the Middle Ages as “domus fortis supra Lonetam” - strong house on the Lahn. Over the years this gradually becomes Lahnstein, the town’s present name.
When the Romans abandon the Rhine Valley in the 5th century AD, the Burgus loses its military significance. From now on it is used as a residential castle. It is officially mentioned for the last time in the year 1549 when it is nothing but a ruin.
The Roman fortification is only rediscovered in 1914. Extensive archeological excavations uncover it in 1926. In order to preserve this important cultural monument, the excavations are filled in again in 1946 using bombing rubble from World War II. The Roman Burgus has been waiting for further investigation ever since.