Begun as a three-aisle hall church at about the same time as the town Ribnitz was founded, the oldest pre-Romanesque parts of the St. Mary's Church are located in the western outer wall of the building. Pilister corner strips, a rounded frieze and lanset windows are amongst other remanents of this first church.
In the 14th century, the church was enlarged by the addition of two bays, and decorated by the addition of peaked arch portals in the north of south of these. After a 1455 fire, the building was rebuilt with a pentagonal choir bay and a massive ornamental helm on the top of the spire. The Great fire of 1759 destroyed this ornamental helm, as well as the building's vaulting and medieval interior. Under instruction of the court masterbuilder Johann Jachim Busch of Ludwigsluster, the tower's roof and its interior was rebuilt in a Gothic style.
The centre aisle of the church was distinguished from this time on by a semi-circular barrel-shaped timber supports, the side-aisles by a flat wooden roof. Busch envisaged a pulpit alter, and after the pulpit was relocated into the church nave, the alter was completed with the addition of the Ludwigluster court painter J.H. Surlandt; the image is a copy of Annibale Carraci's 'The Burial of Christ'. The church's northern and southern side-chapels were never restored due to insufficient funds, with the foundations also removed. Between 1841 and 1843, Georg Adolph Demmler oversaw the addition of a latern to the of a Baroque-style tower crown, heighening the tower, which still offers a sightseeing platform to visitors. In the 1970s, the church was threatened by structural damage, losing once more much of its interior: the 1883 organ, built by Friese of Schwerin, was removed. After 1980, the church was renovated, the interior again altered and a winter church on the site added.
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.