Clairmarais owes its origin to the famous Cistercian abbey founded by St. Bernard in 1140. He gave the village the name of Claromarisco (later to be Clarus Mariscus and then Clermarez) because of the huge marshes and many rivers in the vicinity. The Dutch Klaarmares and West Flemish Cleremeersch names reflect the nature of the terrain, too. Clairmarais became a fully-fledged common in 1790 when the abbey was going to be destroyed and sold as a national asset during the French Revolution.
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.