Santo Stefano d'Aveto Castle controlled the roads from the Apennines to Emilia. It was probably built int the 12th century, first time documented in 1164.
The castle that presents itself now is an interesting pentagonal structure with ramparts on four of the five perimetral corners. In ancient times the arms square could be reached, an area onto which the different rooms on the ground floor open, using drawbridges that were easy to lift in case of attacks.
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.