The Barbara Baths (Barbarathermen) are a large Roman bath complex designated as part of the Roman Monuments, Cathedral of St. Peter and Church of Our Lady in Trier UNESCO World Heritage Site. The Barbara Baths were built in the second century AD. The extensive ruins were used as a castle in the Middle Ages, then torn down and recycled as building material until the remains were used for constructing a Jesuit College in 1610.
Only the foundations and the subterranean service tunnels have survived, but the technical details of the sewer systems, the furnaces, the pools, and the heating system can be studied better than in the other two baths of Trier.
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.