[2] The westernmost, Rosenberg Castle was built by the bailiff of Murbach-Lucerne Abbey in 12th century.

They were in the service of the Freiherr of Brienz-Ringgenberg and around 1200 crossed over into Unterwalden, where they established the castle in Giswil.

At some point, the castle was abandoned and partially demolished, probably to provide building material.

Additional artifacts were discovered in 1887 during construction of the Brünig railway line near the castle.

The low entrance was probably added in the early 16th century and is located on the south west corner.