Rosenau Castle (Ruin) (Königswinter)

The castle ruin Rosenau stands on the Rosenau mountain in the Siebengebirge Nature Park in North Rhine-Westphalia. It is located in the municipal area of Königswinter between the Nonnenstromberg and the Großer Ölberg.

It is still not known when the hilltop castle was built. It probably belonged to the Archdiocese of Cologne, as the complex fit well into its castle system, which protected the southern flank of the archdiocese with Rolandseck Castle, Godesburg Castle, Drachenfels Castle, and Wolkenburg Castle.

In a document dated February 27, 1222, the Rosenau castle complex and its then owner Dietrich are mentioned for the first time. Dietrich von Dorndorf came from the lower nobility and from that time on named himself after the castle he ruled, also Dietrich von Rosenau (Dietrich von Rosenouwe). After his death, his widow Agnes sold the Rosenau in November 1243 to Heisterbach Abbey. The contract explicitly assured the new owner the right to destroy the castle, which was a very unusual process.

After a second sales contract was concluded in 1249, because a daughter-in-law of Agnes von Rosenau had raised an objection, the castle was destroyed by Heisterbach Abbey around 1250. The stones were probably reused and served as building material for the monastery buildings.

In 1885, the residential area Rosenau, located near the castle ruin, had 20 inhabitants in three buildings. Between 1896 and 1898, the then owner Anselm Bachem had a hotel built on the site. During the subsequent construction of paths and a pavilion in 1902, walls were uncovered, which the Rhenish provincial conservator Edmund Renard described as "[...] an elongated rectangle of about 18 m width and 30 m length [...]". After the hotel was severely damaged in World War II, the current owner, IG Bergbau und Energie, had the building demolished.

The castle ruin today consists of the up to six-meter-high remains of a ring wall made of trachyte, which rise on the south side of an artificially created plateau. They were preserved in 1990/91 with the help of IG Bergbau und Energie, the state of North Rhine-Westphalia, and the city of Königswinter.