The present building of Nysted Church dates back to c. 1300. Originally it consisted of a central nave with a three sided apse to the east. The impressive tower was built a century later. In 1643 a spire was added, and in 1935 this was covered by copper. The Raben-Levtzau family of Aalholm Castle had their own chapel built in 1782. According a rumour there is a secret underground passage from the castle to the church. It hasn't been however found. The church was thoroughly renovated in 1864.
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.