Alt-Lägern Castle (Ruin) (Boppelsen)

The ruin is located on the narrow ridge of the Lägern, west of the so-called "Hochwacht".

Based on the small finds secured, Lägern Castle – also known as Hohen- or Altlängern – must have been built in connection with the founding of the town of Regensberg by Baron Lütold V. between 1244 and 1246, as the seat of his vassals there, the Knights of Lägern. Also according to the finds, the castle must have been destroyed before 1300 – possibly in the so-called Regensberg Feud in 1267 – after which the Lords of Lägern became completely impoverished and died out.

Between 1902 and 1904, extensive excavations took place under the supervision of the Antiquarian Society of Zurich, but these could not be completed due to lack of funds. The enclosing walls describe a rectangle of approximately 67 m by 20 m. Some interior walls indicate residential and utility buildings. No remains of a tower are present. In 1982, the partly heavily damaged walls were repaired by the municipality of Boppelsen and the Canton of Zurich.