The Church of the Holy Archangels Michael and Gabriel in Nesebar, Bulgaria, is a partially preserved medieval Eastern Orthodox church, built in the 13th or 14th century. As part of the Ancient Nesebar UNESCO World Heritage Site, it stands in the old town and has been under state protection since 1927. The church, with a cross-in-square plan, features three apses and a large narthex. Despite partial preservation, it remains culturally significant, boasting opulent external decoration characteristic of Nesebar's medieval religious architecture. The architectural style, opus mixtum, incorporates alternating rows of brickwork and stones in a chequered pattern.
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.