The imposing red brick church in Keldby is one of the three Møn island churches decorated with frescos by the Elmelunde Master, probably towards the end of the 15th century. In the so-called Biblia pauperum style, they present many of the most popular stories from the Old and New Testaments. There are also a number of earlier frescoes in the church dating back to about 1275.
The original nave and choir were constructed in the first half of the 13th century. Around 1480, the nave was expanded with cross vaults and the choir was heightened with limestone. The tower was added in the 16th century and a small sacristy was built about 1700. The richly carved altar triptych and the pulpit are from 1586.
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.