The Apollinariskirche is a church on the site of a Roman temple on the Apollinarisberg, a hill above the German town of Remagen. That hill was known as the Martinsberg in the 5th and 6th centuries, presumably after a Frankish chapel there dedicated to Saint Martin, patron of the Franks. In the 9th century this chapel was replaced by a Romanesque church.
In 1110 the Benedictines of the Michaelsberg Abbey, on the initiative of the people of Remagen, set up a provost there. The relics of Saint Apollinaris of Ravenna probably arrived on the mountain at the end of the 14th century, since a pilgrimage to the Apollinarisberg is recorded in 1384. The sarcophagus is the main relic in the 14th century crypt of the church.
A new Neo-Gothic church was built on the site from 1837 to 1852.
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.