The castle ruin Rudelsburg lies on the east bank of the river Saale atop a rocky shell limestone ridge, approximately 85 metres (279 ft) above the river and above Saaleck, a suburb of the town of Bad Kösen in the Burgenlandkreis district in Saxony-Anhalt, Germany. The Rudelsburg was built in the Middle Ages by the Bishop of Naumburg and served to secure trade routes such as the Via Regia through the Saale Valley.
The Rudelsburg was a point of conflict between the bishops of Naumburg and the Margraves of Meissen belonging to the House of Wettin. The castle occasionally served various noble families as a residence, until it was destroyed in the Thirty Years' War and thereafter fell into disrepair. In the early 19th century the Rudelsburg became a popular tourist destination thanks to the romanticisation of mountains and the rise of hiking as a pastime. It was considered one of the most beautiful of the castles on the river Saale and exceeded mere regional fame from 1855 onwards as the annual meeting place of the Kösener Senioren-Convents-Verband, the oldest union of student fraternities with delegates from all German-speaking countries. The Rudelsburg still represents a particular attraction and lies on the southward course of the Romanesque Road (Ger:Straße der Romanik), a holiday route in Saxony-Anhalt.
The Rudelsburg was constructed in the Middle Ages with a central ward divided into several sections and surrounded by an outer ward. The stones of the outer ward were largely reused in the 18th century and it is no longer recognisable; only parts of the wall in the east and south are still there. The outer ward was unusual to the extent that it was built higher up than the central ward was.