Schloss Altenburg

Brugg, Switzerland, Switzerland

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Schloss Altenburg, situated in Altenburg near Brugg in Switzerland's Aargau canton, originated as a Roman fortress around 370 AD during Emperor Valentinian I's reign to guard a ford on the Aare River as part of the Limes Germanicus defenses.

In the late 10th century, it became a medieval castle built atop the ruins by Lanzelin, an ancestor of the Habsburgs, serving as their initial residence until they shifted to Habsburg Castle around 1020, after which it functioned as a bailiff seat and was gifted to Königsfelden Monastery in 1397.

Rebuilt in the 16th century with a Gothic tower house, it transitioned under Bernese control post-Reformation, later becoming a youth hostel in 1941 while preserving Roman walls up to 7.5 meters high, now recognized as a Swiss heritage site.