Dattenberg Castle was built around 1220 by the lower nobility Lords of Dattenberg as their ancestral seat. Around 1320, Wilhelm de Dadenberg sold the castle to the Archbishopric of Cologne, who granted it as a fief to the knight Rollmann von Sinzig in 1331 on behalf of Altenahr. Rollmann's grandson and his descendants bore the name von Dattenberg. Through Elisabeth von Dattenberg, wife of Goddart von Lülsdorf, the castle passed to her son Albrecht von Lülsdorf, who was granted possession in 1572. When Albrecht's successor, Ludwig von Lülsdorf, died without male heirs in 1664, his son-in-law, Johann Friedrich Raitz von Frentz zu Gustorf, received the fief in 1667, but it was confiscated as lapsed after his death in 1675. In 1624, the castle was already described as ruined.
Owned by the Prussian state, the castle was sold to Cologne's Appellate Court Councilor Dahmen in 1822. It then came into the possession of Josef Stoppenbach, a notary in Cologne, in 1837. Stoppenbach built a two-story country house with a tower-like staircase and farm buildings using rubble stones. The most significant construction work was carried out in 1840, but Stoppenbach went bankrupt in 1848, and his property was auctioned off in 1850. Otto von Mengershausen took over Burg Dattenberg until he handed over ownership to Berlin architect Adolf Fuchs in 1887, who then converted it into a villa resembling a castle in 1890. Adolf Fuchs cultivated vineyards and orchards in Dattenberg. From 1929 to 1938, his descendants had to rent out the property to Father Rudolf Schütz, who wanted to train young girls of all social classes according to the principles of the Catholic Laity Apostolate through his institution 'Heim in der Sonne.' In 1939, the Nazi state established a Landjahrlager on the premises, sometimes for boys and sometimes for girls. At the end of World War II, German soldiers entrenched themselves on the castle grounds until they were occupied by the Americans. After the property came into the possession of the District of Cologne in 1949, it was used as a rural boarding school by the Erft District until 1996 and became privately owned by Karin and Karl Schultz in 2003.
The former high castle complex consisted of a circular main castle, a rectangular enclosure wall, and a flanking tower at the northeastern corner. Today, it still shows the approximately 11-meter-high stump of the centrally located keep (residential tower) with a diameter of 8.5 meters, as well as a moat carved into the slate rock. The forecourt has been rebuilt in modern times. The most impressive part of the partially restored fortification is the ruin of the keep, which can only be viewed from the outside.
The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.