Nassenfels castle dates from the 12th-13th century. The first reference to the castle is dated to 1245, when Count Gebhard III of Hirschberg was assassinated when he was besieging Nassenfels castle. The castle was reconstructed and enlarged later and the current appearance dates from c. 1400. The three towers were built by bishop Friedrich von Oettingen. Nassenfels was again restored in 1464 and 1699. in 1807 the castle was sold to private owners and used as a quarry.
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.