Burgruine Hohenburg auf Rosenberg is a ruined medieval castle probably erected in the late 11th century. The castle was first mentioned as castrum Hohenburc in an 1142 deed. It was then the seat of a Bavarian noble family, who as Counts of Lurn administered the Lurngau region within the Duchy of Carinthia. The last count, Altmann, had become Prince-Bishop of Trent in 1124, and upon his death in 1149, the castle was bequested to the Archbishopric of Salzburg and became the seat of episcopal ministeriales.
Under the mediation of Duke Ulrich III of Carinthia, in 1263 a division of the property was arranged between the Salzburg archbishops and the neighbouring Counts of Ortenburg, heirs of the extinct Counts of Lurn, who had aspired the Hohenburg estates for decades. In 1311 Archbishop Conrad IV of Salzburg enfeoffed a part of Hohenburg Castle to the sons of late Count Frederick I of Ortenburg (1247–1304). Nevertheless the residence became less important when it was replaced by nearby Feldsberg Castle as administrative seat of the Salzburg possessions. When the Ortenburg dynasty became extinct in 1418, their possessions passed to the Counts of Celje.
Today only ruins remain. The castle was probably destroyed in the 15th century conflicts between the Counts of Görz and the Habsburg emperor Frederick III over the heritage of Count Ulrich II of Celje. The former chapel was rebuilt as the Baroque St Mary's pilgrimage church (Maria in Hohenburg) in 1707.
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.