Brindisi di Montagna Castle was built around 1200 and is situated on a large rocky ridge. The architecture is characterized by three main elements: The central part (a long the rocky ridge of the hill).The northern part, with the turret for lookout (later transformed by the Antinori family into the chapel of San Michele) and the southern part where there are few but significant wall traces embedded in the rocky elements.
Its defensive function is evident both from the presence of arrow slits and its position overlooking the intersection of the two routes leading to the fortress. It differs from the Swabian castles in terms of its layout, formal characteristics, and construction techniques, as it predates others built by Frederick II. Instead, it has undergone numerous transformations since the Angevin rule.
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.