Possibly built on the foundations of a Roman castrum fortress, the Moosham castle was first documented in a 1191 deed. It was seized by the Prince-Archbishops of Salzburg about 1285 and from the 14th century onwards served as the residence of an episcopal burgrave. Under the rule of Prince-Archbishop Leonhard von Keutschach from 1495, the castle was rebuilt and extended. In 1520 it became an administrative seat of the Lungau region and was besieged during the German Peasants' War of 1524–25. Archbishop Wolf Dietrich Raitenau stayed here on his flight from Salzburg in October 1611, shortly before he was captured.
Archbishop Count Hieronymus von Colloredo dissolved the Moosham bailiwick in 1790, whereafter the castle decayed. In 1886 the Austrian explorer and patron of the arts Count Johann Nepomuk Wilczek purchased the ruin and had it restored. Up to today the complex is a private property, though its rooms featuring Wilczek's extensive art collection are accessible to the public.
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.