The Byzantine Bath in Thessaloniki is one of the few and best preserved of the Byzantine baths that have survived from the Byzantine period in Greece.
The baths date to the late 12th/early 13th century, and functioned continuously until 1940, when they shut down probably due to World War II and the German occupation of Greece. The Byzantine sources do not mention it, hence it is likely that it originally belonged to a monastery complex.
The bath's long use led to numerous alterations of the original structure over time. The original architecture follows the typical conventions of Roman baths. The original entrance in the south leads to the rectangular frigidarium rooms, which were used as dressing rooms. Then came two vaulted tepidarium rooms and finally two caldarium rooms. The latter were square in shape and featured hypocausts below the floor. One was covered by a dome supported by an octagonal base with eight windows, the other had a domed ceiling. To the north of the baths was the cistern that provided it with water, with a hearth beneath to warm it. In Byzantine times the building was alternately used by men and women, but in the Ottoman period the bath was divided into exclusively male and female sections, by blocking off each pair of rooms from each other.
The bath was one of several in the city, but is the only surviving in Thessaloniki and the largest and most complete of the handful of Byzantine baths surviving elsewhere in Greece.
In 1988, it was included among the Paleochristian and Byzantine monuments of Thessaloniki on the list of World Heritage Sites by UNESCO.
Following four years of restoration work, the bath was re-opened to the public as a museum and cultural space in June 2015.
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.