Hinterburg is one of the four castles in a string along the Neckar River, built by the von Steinach family in the 1100s. It is the oldest of the four, serving a strategic purpose in allowing the lords to observe the Neckar and Steinachtal. One of the earliest records mentions Bligger von Steinach, c. 1160. His son, Bligger II, who was also a famous minstrel of the time, added much of the outer wall that helped drastically improve the castle's defensive posture. At one time it also had a dry moat with a drawbridge. The castle continued to be used up until the 1600s, largely in the service of the Elector Palatine. Afterwards it began to decay from neglect as it lost its importance in the era of cannon. There is no indication that it was ever seriously besieged.
References: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.