The Dominican Monastery in Ústí nad Labem was founded in 1186. The church was remodelled in Baroque style in 1718-1722 during extensive reconstruction designed by Litoměřice architect Octavio Broggio. At the wish of the Prior of Ústí, he based his design of the St Adalbert Church on the model of the Prague Church of St Ursula. Under the communist regime it was used for storage and later on, whitewashed and stripped of all furnishings, converted into an exhibition hall. The wall paintings from 1928 were probably by Albin Müller. The original monastery was a single-wing structure at first (in 1617-1650), its enlargement being impossible for financial and political reasons, the second wing was added during the Baroque reconstruction. The south wall of the church and monastery merges with the city walls.
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.