The Mountain Church or Saint Nicholas Church is a Romanesque basilica built between 1198 and 1209 and consecrated to Saint Nicholas. In the 15th century the Mountain Church underwent several renovations, which gave it a more late Gothic appearance. The two characteristic tower spires are built in that period. The lower part is still original. In 1580 the Dutch Reformed Church took the temple and renamed it the Mountain Church. All catholic features were removed from the interior, which was very common to do. The wall paintings were covered with white chalk.
In 1967 the church was disestablished and its property transferred to the Municipality of Deventer. The building is used as an exhibition center and concert hall. From 1991 until 2005, the church was used for temporary exhibitions by Museum de Fundatie.
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.