taken from the on-site information board:
Community of Sylt-Ost
- Tinnum-Burg -
The Tinnum-Burg (Burg means fortress or castle) was built on the oldest clay layer of the Sylt Südermarsch around the time of the birth of Christ. The enclosure is located on a marsh priel which was connected to a channel in the Westerland Geest. The lowland to the west and north of the enclosure shown on maps from the 18th and 19th centuries as a more or less contiguous silt up lake area. Whether the channel was ever navigable is debatable. Before the marshes were dyed in 1938, the enclosure jutted out of the water like an island during storm surges.
Excavations in 1870, 1948 and 1976 provided evidence that the Tinnum fortress was one of the circular rampart built on the North Frisian islands in the early Roman Empire. It was used again in the 8th to 10th century after a phase in which it lay fallow and mossed up inside (interior construction with sod wall houses). The rampart visible today, which was built over the rampart from the time of the birth of Christ, also dates from this time.
The circular rampart built in the early Roman Empire are interpreted as local Germanic places of worship (sacrificial sites) after a detailed analysis of the excavation results of the Archsum fortress. Except for the Tinnum-Burg and the Lembecksburg on Föhr, there are no comparable monuments of this type in Schleswig-Holstein.