The Church of Saint Sofia is an Eastern Orthodox church in Nesebar, eastern Bulgaria It is situated in the old quarter of the town which is part of the UNESCO World Heritage Site list and of the 100 Tourist Sites of Bulgaria.
The church is located in what is supposed to have been the center of the ancient city. It is a three-naved unvaulted basilica with a semi-circular apse, a narthex and an atrium. The church has a total length of 25.5 m and a width of 13 m. The division into three naves was effected by two rows of five pillars each. The middle nave ends to the east with a big closed apse, round outside and three-sided inside. There are three arched windows on the eastern wall above the apse. The basilica used to have a double-sloped roof which has not been preserved. From the inside the church used to be plastered and then painted with frescoes. The whole floor used to be covered with mosaics made out with little coloured stones. It has mixed masonry of stone and brick and is the largest of the Nesebar churches whose overground structure has survived.
The basilica was constructed in the late 5th and early 6th century. Its present appearance was dated from the beginning of the 9th century when it was reconstructed. During the Middle Ages it served as a cathedral for the bishopric eparchy centered in Nesebar. In 1257 the church was looted by the Venetians during a campaign against the Bulgarian Empire and many religious relics were taken in the Church of San Salvatore in Venice. The basilica was abandoned in the 18th century.
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.