In 1100, a nobleman named Heinrich named himself after the old Clingenburg (castle). He belonged to the noble family of Reginbodo. The Clingengurg castle was built around 1160-1170 by Conradus Colbo, who was cup-bearer to Emperor Friedrich Barbarossa.
About 1250, the Bickenbach noble family moved into the castle; the Bickenbachs later held many influential offices in the Holy Roman Empire and many a time turned up in Imperial politics as brokers.
After the Bickenbachs died out in 1500, the town, castle and lordly domain passed to the Archbishop of Mainz. Clingenburg castle was destroyed by the French in the late 17th century and never rebuilt. It remained a ruin.
In the 20th century Clingenburg was opened up to tourism with a restaurant and a lookout platform affording visitors a view over the old town and the Main valley. Since 1994, the Clingenburg-Festspiele have been taking place, drawing many visitors each year with changing plays and musicals.
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.